Great video!!! Thanks. Just did mine (2004 67K miles - burned exhaust valves #3 cylinder, low compression). Actually had to do the job twice! because Autozone sold me a reman (American Cylinder Head) that had a cracked water jacket, so coolant leak when put back together. Used your "turnbuckle" system which worked great! Also bought the special tools to hold the timing chain but with the wire/turnbuckles they aren't totally necessary. Second time I did the job I machined the "special wedge tool" on my CNC that goes down into the timing chain cover and secures the chain from falling down off the crankshaft sprocket. It also makes the whole pain of releasing the timing chain tensioner and retracting it unnecessary. You can just pop the timing sprockets back on. I also bought an 8mm 1/2 inch drive allen socket and cut it down just short enough to go into the new exhaust timing gear bolt, and used with a "bolt stretch" torque wrench you don't have to pull the radiator shroud off (like another 2hrs of work). I used the "pound on the headbolt" technique and only broke 3 headbolts....2 were the very rear where you can't really pound them. Amazon sells a great kit for extracting them similar to the GM tool but MUCH cheaper. smile.amazon.com/gp/product/B006YDQ812/ref=oh_aui_search_detailpage?ie=UTF8&psc=1 Thank you again for the video, it was really helpful!
I disconnected the battery let it set for 20 minutes reconnected the battery and turn the key on and waited a couple minutes before I turn the key to the start position the truck seems to hang up on something until you bump it two or three times then it finally turned over and runs it's very rough I can not even go down the street in it now it is overheating instantly you are the coach from today
Just wanted to say thank you for these 2 videos,,, I used them to guide me along after the my trilblazer valves went bad. Sure helped to see what I was getting myself into.
I have a 2007 TB with just over 100,000 miles. Was getting a P0305 cylinder number 5 misfire code constantly. I changed the plugs (with AC Delco) and swapped coils from another cylinder and still got the misfire code for cylinder 5. I finally did a cylinder leak down and a compression test on all 6 cylinders. Cylinder1: Leakage: 20%, could feel air leaking through throttle body, Compression check: 210 PSI, Cylinder2: Leakage: 9%, could not feel any leakage, Compression check: 220 PSI, Cylinder3: Leakage: 22%, could feel air leaking through throttle body, Compression check: 215, Cylinder4: Leakage: 11%, could not feel any leakage, Compression check: 220 PSI, Cylinder5: Leakage: 69%, I did a smoke test and could not only see smoke coming out the tail pipe but could also hear the air hissing into the exhaust. Compression check: 160 PSI, Cylinder6: Leakage: 7%, could not feel any leakage, Compression check: 220 PSI. Looks like I'm pulling the head.
You did a great video. The locks on the electrical plugs; the removal of the broken bolts would of helped I think. Not everyone is as experienced as you. Using bungee cords (heavy rubber type works well for holding the timing chain also. You helped me to get the exhaust cam actuator back on. Thanks. It had me stymied. Also the three small bolts at the front need to be degree tightened also. I broke one off tightening it. Made a guide and extended drill bit and got it out. Whew!!!! Thanks again!
John R McLellan, CH Glad to help. I hate torque to yield bolts for these very reasons. Nothing like stretching $50 bolts to rack your nerves. The small ones are the worst, they can't handle much torque.
***** I ended up having to pull the front cover to release the timing chain tensioner which meant dropping the oil pan which meant dropping the steering mechanism and front differential. Did you release the tension yourself or did you get someone else to do it? I am still wondering why you didn't answer my request as to how you did it. Once I pulled the tensioner out it proved very simple, contrary to GM's "it can't be done"BS.
I specifically Recall mentioning I just used a coathanger bent into a hook to grab the release lever from the top, but that could have been on another comment, ever since youtube forcefully merged google + the comments system has been a mess.
Thanks for posting this. I just finished getting my head out and my problem IS burn exhaust valve. Unfortunately, I broke 8 or 9 head bolts, but I didn't freak out because everywhere I read it said to expect that. I tried shocking the bolts and I didn't jerk the wrench to loosen them. It just seems unavoidable. Also, in my Chilton book and on this video, I didn't see that you have to unbolt the Timing chain guides before you try to take the head off. I wound up braking one of mine so I'll have to take the front cover off to replace. Not a huge deal, it's only $23. There's also a piece mounted to the back of the head that is a sort of pass through for 2 (what look a cooling and a vent hose). That wound up breaking also when I was trying to get the head out. It's very fragile. So I'll have to get on of those too.. Thanks again.
I can't say thank you enough for your help My trailblazer will sit there and idol up to three hours at about 160° maybe 180 AC or heat on but the minute you drive it it starts to heat up I thought this might help you some hope to hear from you soon
Well done video. i have an 03 with 260k on the motor. no major issues but i was considering tearing it apart in the summer and replace all seals and clean up carbon.
Not worth it unless its leaking IMO. Working on these engines is too tedious. These engines were notorious for carbon buildup and clogged injectors. Decarb services and injector cleanings are routine maintenance and can be done without taking everything apart.
I'm talking about the actuator that goes into the passenger side engine block right at the top and the crankshaft sensor that you right in front of where you put oil in the motor at this is a 4.26 cylinder
+jddllll Oh, That's the camshaft phaser and camshaft sensor. How did the old cam phaser look? Any screens missing, sludge or grit buildup? If you clear the trouble codes do they come back?
no i have not ,when it idles you can hear something going on/off.the old fan you could stop with your hand.i am down to the intake manifold. should i stop and look at the relay.by the way the compression is great no water in oil .,passes the block test,and pressure test..thanx so much john
hey i just got these codes read and hour ago ,,,,C0055 abs....C0201..P0113..P0141... P0300...P0014....I JUST RENTED BLOCK TESTER,,COMPRESSION GAUGE....PRESSURE TESTER FOR RADIATOR....THANKS AGAIN ,HOPE TO HEAR FROM YOU SOON..JOHN
+jddllll P0141 is IAT sensor, probably was started with it unplugged at some point. P0014 is an issue with the variable valve timing. Most likely the Cam Phaser or exhaust cam actuator, these will in turn cause the misfire and the p0300 code. You can clean the cam phaser or replace it, there are other videos on it. If that doesn't fix it you are looking at getting a new exhaust cam actuator.
Hey man not sure if youll reply to this, but ill give it a shot. When you started pulling the head, you removed the wires from the side, then added wires to the top of the chain to keep tension, correct? Then when you had enough clearance, you re-tied the side wires right? Thanks
the coolant was chevy and distilled water...there were some codes .ill look for them..the dash cluster stopped working and while i had it out ,i found the engine lite had been taped over .when i put the cluster back in engine light was still on ,,maybe 6 months later all this started . should i have it scanned now ?
+Alex Rodriguez Wiggle it around. Get fancy with it if you have to, if the bolts are out it should come out without too much fuss as long as it clears everything. One bolt may still be threaded in a little.
+jddllll A leakdown/compression test on all cylinders wouldn't hurt. But first thing I would do is get the VVT problem taken care of. Most code readers will also clear codes.
I have had heat problems with the middle valves on 4.3 's. I am thinking it's because, being in the middle less air circulates & it cannot cool itself as well as it should or needs to. I'm going to try and improvise some sort of air damn to move more air around it Thanks for the vid.
how many total bolts are on the black piece,... after the mount and alt are taken off, the video skips to removing it.. Just trying to understand.. thanks
busboy956 Could be many things. But one of the common issues is a faulty fan clutch relay. The Fan clutch is electronic and is controlled by a solid state relay in the underhood fuse box. It's pretty common for them to burn out and cause overheating.
will you let me know where are the bolts for the parts you are pulling out, the video is so fast I need to get to the valve cover bolts, for your helpp thank you.
manuel viramontes Just follow the perimeter of the valve cover all the way around, you should get them all that way, they are captive in the valve cover so they won't come all the way out.
IM DOING A ENGINE SWAP on a 2004 trailblazer 2wd 4.2 in line 6 . when i try to put motor and tranz together the converter will not spin free.. apart the converter spins free.when i mount the converter in tranz i have waited till i feel the two clunks..please help
+jddllll I think it's supposed to be 3 clunks for the 4l60E. When you bolt the engine to the trans the torque converter should have just a little wiggle room between it and the flexplate before bolting them together, if its tight before bolting the TC to the flexplate then the TC isn't seated all the way. It probably pulled out when removing the engine. You need to rotate it and shake it to get it seated all the way, don't be afraid to be rough with it.
I put a new bottom radiator hose on and New fan relay it's back to doing the same old thing Dryvit 10 minutes and it overheats and just pegs and it's missing worse than ever any suggestions I would appreciate it
How many miles? Have you looked at the water pump at all? Are you adding dexcool or regular green coolant? The two combined will form a thick goo that clogs up, well, everything.
Great video!! Could I ask anyone here at around what mileage Trailblazers start to have this particular problem? Mine is an '05, has 140K on it. Just wonderin' about when this will happen if you can give me a ballpark. Thanks!!
+jddllll A faulty fan relay will cause overheating at a stop, exact opposite of what you have. If compression on all cylinders is good that rules out a head gasket or internal issues other than maybe a blocked coolant passage. Id check for lack of airflow through the radiator, check the hoses, especially the lower one, make shure it doesn't collapse easily. Ive heard of water pumps corroding and causing overheating while driving. Your engine should run around 190-210* when operating properly. What kind of coolant was in it and what kind of coolant have you been adding?
What's connected to the back of the head? How do I remove it? That's all I have left to get the head off. Only broke 2.9 head bolts in the process lol. One still has both pieces connected by .080 worth of a single thread. I was amazed. But back to the question. What is it and how do I disconnect it from the back of the head? Thanks.
Its the plastic AIR tubes for the secondary air injection. I can't remember if its a bolt or pushpin, I think a bolt. I broke mine getting it off but the tubes were intact.
It's a bolt on the passenger side, and a push pin on the driver's side. Like PFUN, I broke off the plastic around the bolt, but when you reinstall it's nor really critical, just use the push pin only. The clearance is so tight I don't think the AIR tube can really move too much.
i just pulled the plugs getting ready to do a leak down test,,i found little specs of water on 3rd cylinder back from the front of motor ,,,should i continue with leak down test ????
I just finished my engine swap on the 2004 trailblazer my transmission will not engage is there any sort of procedure like bleeding or anything that I should unplug and plug back in or any procedure that I should check out I jack the car up and I had nothing now he goes up to about 10 miles an hour and then it just stops working again
Kevin Simon I install the hose from a compression gauge in the #1 cylinder then rotate crank with a ratchet while feeling for air pressure at the end of the hose. When you feel pressure from the hose keep rotating until it stops. At that point you should be able to see dark links in the chain. Line them up with the timing marks on the sprockets and you will be at TDC.
***** Thanks so i have everything back together, just finished getting cam shaft actuator on and torqued, as im rotating the engine to check the timing the cam shaft almost seems to stop for a second and than catches up, any idea what is wrong
+jddllll Its in the video, its the big device in place of a sprocket on the left camshaft, not something you want to replace until you're out of options.
+jddllll Did you set the engine to TDC on Cylinder 1 and line up the timing marks on the new actuator and keep the chain tight during the process? If you clear the codes are any new ones coming up?
When removing any Gm atlas head bolts just use a hex socket with a ratchet or breaker bar and hit the top of bolt/ratchet while loosing the bolts. Go slow most or all will come out.
pfun41 i decided to change my spark plugs on my trailblazer 03 LS 4.2 and found out that two sparks has oil not to much but yes was some oil in there my question is should i need a new valve cover gasket or do i need something else such intake manifold gasket ?? I hope you could help me thanks in advance brother .
First I want to say great video, very informative! My truck started idling rough after a quick trip one night and had to drop it in neutral to keep it from stalling out at stop signs. After running a bunch of tests, your video helped me figure out what could be wrong. Now for my question. I have disassembled my engine to facilitate removal of the head but I have a concern with the timing chain. All of the literature I have seen shows the cam timing marks lining up with the dark links of the timing chain. Mine don't. They're not even close, the dark links are 3 links advanced at TDC. Is this cause for concern? I need to pull the head to get it machined but this has me stopped dead in my tracks. Am I being overly cautious?
+J Allen No, they need to be lined up. Keep rotating the engine until all the marks are lined up when cylinder 1 is at TDC. I wanna say they line up every 14 revolutions or something like that. And make sure you unbolt the timing chain guide. And keep the chain tight!
I got the exhaust cam actuator in and I got crank shaft sensor on the front of the engine installed Do I need to unhook the battery reset any fuses or anything like that
+jddllll disconnect the battery for 20 minutes or so. When you turn the key on just let it sit for about 90 seconds without touching anything before starting.
Im doing the same job right now. I've remove all the head bolts but the head still doesn't want to break loose. Is there something that i'm missing? (only had 5 head bolts that didn't break).
There are several small bolts at the front around the timing chain ares. They are TTY and will have to be replaced like the head bolts. There is one bolt holding the top of the chain guide to the head on the driver side. Take that out and it should break free relatively easily. Keep that timing chain tight.
I have a '05 TB with around 98k miles, my question is: Is there any kind of preventative maintenance I can do in attempt to avoid this problem? or is this issue just sort of a 50/50 chance? I'm not experiencing any problems infact she idles and drives just fine, I was just not aware of this valve problem until I came across this video.
***** Regular decarbonization and fuel injector cleaner may help along with regular maintenance but mostly its just wait and pray. There is a problem with worn valve seats on some engines, it usually shows up very early, around 50k-100k. This one had a burnt valve which showed up around 120k. Typically if you make it past 150k your golden.
@@pfun41 Sweet - I made it past 150K - my idle is 600 rpm. I haven't checked for any oil on the sparkplugs - I don't even know what that means. haha. My mechanic did change the spark plugs and other stuff probably around 150K - and cleaned out the engine or something. I use MMO a big - had some nasty exhaust come out. I guess that can clog up the VVT though? hmmm. I'd like to get 500K out of this beast of a car. Like that Inline Six engine with the great torque.
On your video you take the intake & throttle body off. My question is how do you get to the last bolt by the firewall. What wrench, socket, etc. did you use. What is the tip/trick to getting that one out.
Need to use a 1/4 inch drive socket, on a universal joint, with about a 6 inch extension. Put painters (blue) tape around the universal so it can't "flop" down and you should be able to get it on there. The tape still allows some flex in the assembly.
+jddllll Your codes indicate an issue with the variable valve timing, either the Cam phaser or exhaust cam actuator. This is the cause of your misfire and would be the first thing to take care of as it could potentially have something to do with the overheating as well. you can disconnect the battery to clear codes.
Please help,,,, how many bolts are there to get manifold out????????????? Ben working on truck for 8 hours and I'm tired but not willing to pay mechanic $400
Great job BTW, I think you have the only video on youtube doing this Engine! 4.2L I6 goes in all Trailblazers/Envoys from 2002 to 2009. And it's not a easy job by no means. What would be a decent cost to have this done on a 2004 TB? I just changed my Air Filter, gas filter, Cleaned the Throttle body. I have NO engine light on & in cylinder 3 & 4 the spark plugs had oil on them. This TB never miss fired yet. What would you do? I thought I'd just drive it until I get a light of some kind & then cheek out the problem. Help please?
misael pacheco - do you have the 4.2 ? You shouldn't have valve "covers". It's a inline engine... just one cover. Is your engine only smoking from the dripping oil or do you have smoke from the exhaust too?
these 4.2L engines are pieces of shit. mine had only 90, 000km before it started burning oil like mad. they should have been recalled by GM. it's crazy how GM got away with this piece of shit "engineering". the 4.2L engines are notorious for having shite valve seals. GM can go suck a big PENIS, I will never buy another one of their CRAPHOLE vehicles or any vehicle that bears its parts name. Their shitty transmission cooler line design is even worse, don't get me started on that. what kind of retarded engineers has GM been hiring for the past two decades?
As fast as we live I don't know who can still do that if your job it's completely different than a mechanic. If I can get to that point on removing all that, maybe I won't put it back and I will toss the tools away. And call the scrap truck
Brandon Arnold Drill bit and screw extracter. They break because of the tension on the bolt heads, the remains were actually almost loose in the block.
Thank you for taking time to make this video, I am about to remove the valve cover to replace the gasket and would like to ask if you removed the coolant from the vehicle before you started filming or I can get away by just removing the bolt holding the houses and just moving them to the side long enough to get the valve cover off.
wow i can get a motor with 82k for $900.my problems are over heating and missing.when i saw your video it sounded just like my problems. it has new radiator,thermostat.fan shroud,new fan clutch,,when i put the new radiator it ran good for two months.and now you can only go 5 minutes then it starts boiling over.if you turn the heat on it goes down for about 5 minutes then it sounds like the radiator is about to explode..i tried taking out thermostat it made things worse
So doing it this way, you can leave the AC compressor? Don't have to recover freon? Also, anything you would do different if you did this again? I will be doing this soon on my girlfriend's 05. It overheated and the water pump blew. Replaced the water pump, but there's oil in the coolant. There's also been oil building up in the #3 cylinder for a while, so I think it's time to machine the head and replace the head gasket.
Need to use a 1/4 inch drive socket, on a universal joint, with about a 6 inch extension. Put painters (blue) tape around the universal so it can't "flop" down and you should be able to get it on there. The tape still allows some flex in the assembly.
+Alex Rodriguez Unbolt the PCM, remove the bracket underneith it. Remove the alternator, there's a bolt for the intake manifold behind it that's hard to get to, also pull off the tube in the middle of the manifold, there's a bolt behind there too. The rest are easy to see, the one by the firewall is a PITA. When you have it all unbolted it will come off easily, if it won't move there's a bolt you missed.Don't try to get around removing any of that stuff, you'll only make it more difficult.
137k new radiator .hoses ,thermostat .water pump ,,new plugs ,,map sensor.,,,will only cool down when you turn the heat on,,,that only last about a mile,,, the truck runs great after 2500 rpm
How do you manage to break that many head bolts? That plus the black crud all over cyl. #1 (at least that's all I saw there could be more), leads me to believe yours had a bad head gasket for quite awhile. The excessive heat could've weakened the bolts.. otherwise you're not doing something right. That could also explain the damage to your head. Just sayin'... Anyway, decent video no bullshit and straight to the point, just think you should've done a little more detail for everything you removed for people that aren't mechanics. Not bad though 9/10 stars I say...
You WILL break head bolts on the 4.2 Atlas. That's just the way they are. The 4.2 is known for excessive carbon buildup. Decarbs and throttle body cleaning are standard maintenance for these engines.
Can you email or post a video of this in real time not fast forwarded plz having trouble taking off plastic intake manifold so i can change the valve cover gasket
sammy placencia I can't, the Video file for that part would amount to a few GB. You'll need to remove the PCM, There's a metal bracket under it that has to come out, its held on with a couple nuts. The alternator also has to come out. Once the alternator is out you should be able to see most of the bolts, there is one that's hidden behind the tube in the middle of the manifold. Once you get all the bolts loose it should pop right off, then just maneuver it out of there.
***** Thank you we got it the other day but we had issues how did you take off the last bolt closest to the firewall we couldnt get a tool in there so we just took off all the other ones and kinda pushed it aside and held it in place untill we could take off the valve cover
Mine just started doing a lot of tapping and a little belt squeal. Popped the hood and saw oil down the driver side, all the pulleys and noticeable power loss. Just hit 170k in the old girl. I knew she was about to shit the bed soon and boooooy in the middle of a road trip she did. I knew it was gonna be a valve. I don’t want to 😩😩😩
Hey man I have a gmc envoy 4.2 same truck I can not get the intake manifold out please help I have everything out the alto atop throttle body anything to possibly block it just seems to be like stuck in place Please help asap thank you gladly appreciated
+jddllll Contunue with the leak down though it sounds like you have a blown head gasket. Are you shure it's water and not gasoline? if it is indeed water then safe bet the head gasket is blown, which explains all of you're problems.
Lets see I've replaced the fan clutch, soldered new instrument clusters then bought a new instrument panel now some of those are going bad, couple of speakers have blown, 3rd cylinder was leaking and was quoted an estimate of 2500-4000 from chevy dealership where vehicle was purchased but i got lucky with a totaled gmc with 80k on the 4.2l replaced with that and paid 400 for engine and 50k miles later 3rd cylinder came back to bite, a/c broke. If this isn't just a simple coil fix for 3rd cylinder I'm done wasting money, I love my car but I've got to find something else...good luck to anyone else who dares so this job or pull the motor it was a pain in my ass then and I'm not going through the same nightmare twice.
Premature valve seat wear problems affected the 4.2 up until 05. They redesigned the head for the 06 model year, which eliminated the valve problems and upped the compression a bit with a pcm tune to match. Older low mileage 4.2s are a gamble, valve problems usually show up by 100-150k if they're going to. When a certain engine has inherent internal issues I find it better to fix them rather than replace with a used unit, as they usually have the same problems later on. I'm dealing with a Dodge 4.7 right now.
Great video!!! Thanks. Just did mine (2004 67K miles - burned exhaust valves #3 cylinder, low compression). Actually had to do the job twice! because Autozone sold me a reman (American Cylinder Head) that had a cracked water jacket, so coolant leak when put back together. Used your "turnbuckle" system which worked great! Also bought the special tools to hold the timing chain but with the wire/turnbuckles they aren't totally necessary. Second time I did the job I machined the "special wedge tool" on my CNC that goes down into the timing chain cover and secures the chain from falling down off the crankshaft sprocket. It also makes the whole pain of releasing the timing chain tensioner and retracting it unnecessary. You can just pop the timing sprockets back on. I also bought an 8mm 1/2 inch drive allen socket and cut it down just short enough to go into the new exhaust timing gear bolt, and used with a "bolt stretch" torque wrench you don't have to pull the radiator shroud off (like another 2hrs of work). I used the "pound on the headbolt" technique and only broke 3 headbolts....2 were the very rear where you can't really pound them. Amazon sells a great kit for extracting them similar to the GM tool but MUCH cheaper.
smile.amazon.com/gp/product/B006YDQ812/ref=oh_aui_search_detailpage?ie=UTF8&psc=1
Thank you again for the video, it was really helpful!
I'd lose my shit If I had to do this twice. Guess you learned the hard way about Autozone parts.
I disconnected the battery let it set for 20 minutes reconnected the battery and turn the key on and waited a couple minutes before I turn the key to the start position the truck seems to hang up on something until you bump it two or three times then it finally turned over and runs it's very rough I can not even go down the street in it now it is overheating instantly you are the coach from today
Just wanted to say thank you for these 2 videos,,, I used them to guide me along after the my trilblazer valves went bad. Sure helped to see what I was getting myself into.
I have 347000 miles on mine still runs good. 2006. 4.2
Thank you SO much for posting these videos. Very impressive work. Not sure I will be taking this on myself.
I have a 2007 TB with just over 100,000 miles. Was getting a P0305 cylinder number 5 misfire code constantly. I changed the plugs (with AC Delco) and swapped coils from another cylinder and still got the misfire code for cylinder 5. I finally did a cylinder leak down and a compression test on all 6 cylinders.
Cylinder1: Leakage: 20%, could feel air leaking through throttle body, Compression check: 210 PSI, Cylinder2: Leakage: 9%, could not feel any leakage, Compression check: 220 PSI, Cylinder3: Leakage: 22%, could feel air leaking through throttle body, Compression check: 215, Cylinder4: Leakage: 11%, could not feel any leakage, Compression check: 220 PSI, Cylinder5: Leakage: 69%, I did a smoke test and could not only see smoke coming out the tail pipe but could also hear the air hissing into the exhaust. Compression check: 160 PSI, Cylinder6: Leakage: 7%, could not feel any leakage, Compression check: 220 PSI. Looks like I'm pulling the head.
Yep, time to rebuild the head.
Yours is the only video I found, thanks for posting it. So glad I didnt start this, more than I want to take on. Taking it the garage.
You did a great video. The locks on the electrical plugs; the removal of the broken bolts would of helped I think. Not everyone is as experienced as you. Using bungee cords (heavy rubber type works well for holding the timing chain also. You helped me to get the exhaust cam actuator back on. Thanks. It had me stymied. Also the three small bolts at the front need to be degree tightened also. I broke one off tightening it. Made a guide and extended drill bit and got it out. Whew!!!! Thanks again!
John R McLellan, CH Glad to help. I hate torque to yield bolts for these very reasons. Nothing like stretching $50 bolts to rack your nerves. The small ones are the worst, they can't handle much torque.
***** I ended up having to pull the front cover to release the timing chain tensioner which meant dropping the oil pan which meant dropping the steering mechanism and front differential. Did you release the tension yourself or did you get someone else to do it? I am still wondering why you didn't answer my request as to how you did it. Once I pulled the tensioner out it proved very simple, contrary to GM's "it can't be done"BS.
I specifically Recall mentioning I just used a coathanger bent into a hook to grab the release lever from the top, but that could have been on another comment, ever since youtube forcefully merged google + the comments system has been a mess.
Thanks for posting this. I just finished getting my head out and my problem IS burn exhaust valve. Unfortunately, I broke 8 or 9 head bolts, but I didn't freak out because everywhere I read it said to expect that.
I tried shocking the bolts and I didn't jerk the wrench to loosen them. It just seems unavoidable.
Also, in my Chilton book and on this video, I didn't see that you have to unbolt the Timing chain guides before you try to take the head off. I wound up braking one of mine so I'll have to take the front cover off to replace. Not a huge deal, it's only $23.
There's also a piece mounted to the back of the head that is a sort of pass through for 2 (what look a cooling and a vent hose). That wound up breaking also when I was trying to get the head out. It's very fragile. So I'll have to get on of those too..
Thanks again.
Your video was well done. You have the patience of Jobe. Thank u for sharing and I see in comments you have been very supportive to others.
I wish I knew how to tore apart that big black plastic thing where the throttle body seats that covers the injectors rail.
Intake? It doesn't come apart.
I can't say thank you enough for your help My trailblazer will sit there and idol up to three hours at about 160° maybe 180 AC or heat on but the minute you drive it it starts to heat up I thought this might help you some hope to hear from you soon
Well done video. i have an 03 with 260k on the motor. no major issues but i was considering tearing it apart in the summer and replace all seals and clean up carbon.
Not worth it unless its leaking IMO. Working on these engines is too tedious. These engines were notorious for carbon buildup and clogged injectors. Decarb services and injector cleanings are routine maintenance and can be done without taking everything apart.
They say the valve seats wearing down is due to the EGR that sits right beside the heads creating too much heat
Very well made video, also I would like to add this is pretty much the same way to take apart the i5 on a Chevy Colorado & GMC Canyon.
Wow that is a brave undertaking from where i am sitting. Good luck w the repair!
I'm talking about the actuator that goes into the passenger side engine block right at the top and the crankshaft sensor that you right in front of where you put oil in the motor at this is a 4.26 cylinder
+jddllll Oh, That's the camshaft phaser and camshaft sensor. How did the old cam phaser look? Any screens missing, sludge or grit buildup? If you clear the trouble codes do they come back?
Mi pregunta es en que momento quitastes los tornillos de caveza si siempre se capan
no i have not ,when it idles you can hear something going on/off.the old fan you could stop with your hand.i am down to the intake manifold. should i stop and look at the relay.by the way the compression is great no water in oil .,passes the block test,and pressure test..thanx so much john
hey i just got these codes read and hour ago ,,,,C0055 abs....C0201..P0113..P0141... P0300...P0014....I JUST RENTED BLOCK TESTER,,COMPRESSION GAUGE....PRESSURE TESTER FOR RADIATOR....THANKS AGAIN ,HOPE TO HEAR FROM YOU SOON..JOHN
+jddllll P0141 is IAT sensor, probably was started with it unplugged at some point. P0014 is an issue with the variable valve timing. Most likely the Cam Phaser or exhaust cam actuator, these will in turn cause the misfire and the p0300 code. You can clean the cam phaser or replace it, there are other videos on it. If that doesn't fix it you are looking at getting a new exhaust cam actuator.
Hey man not sure if youll reply to this, but ill give it a shot. When you started pulling the head, you removed the wires from the side, then added wires to the top of the chain to keep tension, correct? Then when you had enough clearance, you re-tied the side wires right? Thanks
yes
the coolant was chevy and distilled water...there were some codes .ill look for them..the dash cluster stopped working and while i had it out ,i found the engine lite had been taped over .when i put the cluster back in engine light was still on ,,maybe 6 months later all this started . should i have it scanned now ?
I took out the one were the alternator was but the one behind the tube I must of missed do I have to fully take of the tube to get to it
cameron duchene No, just pull the top of the tube loose and rotate it down. IIRC there is one above and below it.
Thanks for the information. I got 10 bolts lose, but now the problem I'm having is that the manifold is not coming out, it's lose but won't come out.
+Alex Rodriguez Wiggle it around. Get fancy with it if you have to, if the bolts are out it should come out without too much fuss as long as it clears everything. One bolt may still be threaded in a little.
What is the torque number on to 10mm bolts holding onto the valve cover (5:27)?
Would it be the same on 2003 Oldsmobile Bravada 2wd?
+angelisone Snug, they have metal spacers so you can't overtighten them.
89 INCH POUNDS - not ft pounds. Bravada should be the same.
i don't have a way of clearing codes.it wasnt bad.a little grimy but nothing missing...should i try a leakdown test 0n # 4 cylnder ?????
+jddllll A leakdown/compression test on all cylinders wouldn't hurt. But first thing I would do is get the VVT problem taken care of. Most code readers will also clear codes.
I have had heat problems with the middle valves on 4.3 's. I am thinking it's because, being in the middle less air circulates & it cannot cool itself as well as it should or needs to. I'm going to try and improvise some sort of air damn to move more air around it
Thanks for the vid.
Having problem with leaking valve cover gasket on 08 envoy 4.2 a more detailed description would be helpful on replacing it.
Very good job. I like your approach with the chain problem.
how many total bolts are on the black piece,... after the mount and alt are taken off, the video skips to removing it.. Just trying to understand.. thanks
zanzabar123456 10
If this is a common problem then I'm gonna run MMO in the engine. apparently MMO can clog up the VVT though. Any advice? Just synthetic oil then?
Thanks for making and sharing this video! The timing chain trick with the wire will be useful.
I have a 02 Chevrolet Trailblazer and I replaced the water pump joint with the housing brand new and it still overheats, what can be the problem
busboy956 Could be many things. But one of the common issues is a faulty fan clutch relay. The Fan clutch is electronic and is controlled by a solid state relay in the underhood fuse box. It's pretty common for them to burn out and cause overheating.
If I have to pull this transmission back out is there anyway that it can be done leaving the motor in the truck
+jddllll Support the rear of the oil pan with a jack and block of wood, the motor mounts will hold it.
will you let me know where are the bolts for the parts you are pulling out, the video is so fast I need to get to the valve cover bolts, for your helpp thank you.
manuel viramontes Just follow the perimeter of the valve cover all the way around, you should get them all that way, they are captive in the valve cover so they won't come all the way out.
IM DOING A ENGINE SWAP on a 2004 trailblazer 2wd 4.2 in line 6 . when i try to put motor and tranz together the converter will not spin free.. apart the converter spins free.when i mount the converter in tranz i have waited till i feel the two clunks..please help
+jddllll I think it's supposed to be 3 clunks for the 4l60E. When you bolt the engine to the trans the torque converter should have just a little wiggle room between it and the flexplate before bolting them together, if its tight before bolting the TC to the flexplate then the TC isn't seated all the way. It probably pulled out when removing the engine. You need to rotate it and shake it to get it seated all the way, don't be afraid to be rough with it.
I put a new bottom radiator hose on and New fan relay it's back to doing the same old thing Dryvit 10 minutes and it overheats and just pegs and it's missing worse than ever any suggestions I would appreciate it
How many miles? Have you looked at the water pump at all? Are you adding dexcool or regular green coolant? The two combined will form a thick goo that clogs up, well, everything.
I noticed you completely skipped over taking the intake off 😂 that last bolt will have you editing the WHOLE session out of the video
Thanks for this video, I have one of these trucks and I want to keep it going as long as I can, I'll probably scrap it when it gets into a giant wreck
Great video!! Could I ask anyone here at around what mileage Trailblazers start to have this particular problem? Mine is an '05, has 140K on it. Just wonderin' about when this will happen if you can give me a ballpark. Thanks!!
If you make it to 150k or so they usually are good. This one is about to hit 240k now.
should i put it back together and investigate the fan relay
+jddllll A faulty fan relay will cause overheating at a stop, exact opposite of what you have. If compression on all cylinders is good that rules out a head gasket or internal issues other than maybe a blocked coolant passage. Id check for lack of airflow through the radiator, check the hoses, especially the lower one, make shure it doesn't collapse easily. Ive heard of water pumps corroding and causing overheating while driving. Your engine should run around 190-210* when operating properly. What kind of coolant was in it and what kind of coolant have you been adding?
What's connected to the back of the head? How do I remove it? That's all I have left to get the head off. Only broke 2.9 head bolts in the process lol. One still has both pieces connected by .080 worth of a single thread. I was amazed. But back to the question. What is it and how do I disconnect it from the back of the head? Thanks.
Its the plastic AIR tubes for the secondary air injection. I can't remember if its a bolt or pushpin, I think a bolt. I broke mine getting it off but the tubes were intact.
It's a bolt on the passenger side, and a push pin on the driver's side. Like PFUN, I broke off the plastic around the bolt, but when you reinstall it's nor really critical, just use the push pin only. The clearance is so tight I don't think the AIR tube can really move too much.
How did you removed the throttle body? Like that black piece, can't take it out
i just pulled the plugs getting ready to do a leak down test,,i found little specs of water on 3rd cylinder back from the front of motor ,,,should i continue with leak down test ????
I just finished my engine swap on the 2004 trailblazer my transmission will not engage is there any sort of procedure like bleeding or anything that I should unplug and plug back in or any procedure that I should check out I jack the car up and I had nothing now he goes up to about 10 miles an hour and then it just stops working again
+jddllll any codes?
Would a bent push rod or broken valve spring cause a cylinder to misfire
No pushrods on DOHC. Valve spring maybe if it didn't just smack the piston.
so the alternator has to come off in order to get to the bolt
Yes it does.
Have fun with that 3rd alternator bolt on the bottom!.........it comes out, but not easily.
did you get the post cylinder compression today ??????
cant seem to find the proper timing marks for #1 cylinder at tdc
Kevin Simon I install the hose from a compression gauge in the #1 cylinder then rotate crank with a ratchet while feeling for air pressure at the end of the hose. When you feel pressure from the hose keep rotating until it stops. At that point you should be able to see dark links in the chain. Line them up with the timing marks on the sprockets and you will be at TDC.
***** Thanks so i have everything back together, just finished getting cam shaft actuator on and torqued, as im rotating the engine to check the timing the cam shaft almost seems to stop for a second and than catches up, any idea what is wrong
Kevin Simon Which way are you rotating it? Go clockwise.
ok so where's the exhaust cam actuator at.... just to be sure
+jddllll Its in the video, its the big device in place of a sprocket on the left camshaft, not something you want to replace until you're out of options.
Thank for this video great job
I got the actuator in and the cam sensor right at the front top of the motor it's running worse than ever and heating up twice as fast any suggestions
+jddllll Did you set the engine to TDC on Cylinder 1 and line up the timing marks on the new actuator and keep the chain tight during the process? If you clear the codes are any new ones coming up?
When removing any Gm atlas head bolts just use a hex socket with a ratchet or breaker bar and hit the top of bolt/ratchet while loosing the bolts. Go slow most or all will come out.
That's what they say. In reality they still break.
This engine looks alot like the 3.5 i5 vortex in the H3, would the processes be very similar?
LuckieThePit The I5 and I6 are both part of GM's atlas family of engines, aside from the number of cylinders they are nearly the same.
Thank you
pfun41 i decided to change my spark plugs on my trailblazer 03 LS 4.2 and found out that two sparks has oil not to much but yes was some oil in there my question is should i need a new valve cover gasket or do i need something else such intake manifold gasket ?? I hope you could help me thanks in advance brother .
First I want to say great video, very informative! My truck started idling rough after a quick trip one night and had to drop it in neutral to keep it from stalling out at stop signs. After running a bunch of tests, your video helped me figure out what could be wrong. Now for my question. I have disassembled my engine to facilitate removal of the head but I have a concern with the timing chain. All of the literature I have seen shows the cam timing marks lining up with the dark links of the timing chain. Mine don't. They're not even close, the dark links are 3 links advanced at TDC. Is this cause for concern? I need to pull the head to get it machined but this has me stopped dead in my tracks. Am I being overly cautious?
+J Allen No, they need to be lined up. Keep rotating the engine until all the marks are lined up when cylinder 1 is at TDC. I wanna say they line up every 14 revolutions or something like that. And make sure you unbolt the timing chain guide. And keep the chain tight!
I got the exhaust cam actuator in and I got crank shaft sensor on the front of the engine installed Do I need to unhook the battery reset any fuses or anything like that
+jddllll disconnect the battery for 20 minutes or so. When you turn the key on just let it sit for about 90 seconds without touching anything before starting.
Im doing the same job right now. I've remove all the head bolts but the head still doesn't want to break loose. Is there something that i'm missing? (only had 5 head bolts that didn't break).
There are several small bolts at the front around the timing chain ares. They are TTY and will have to be replaced like the head bolts. There is one bolt holding the top of the chain guide to the head on the driver side. Take that out and it should break free relatively easily. Keep that timing chain tight.
I have a '05 TB with around 98k miles, my question is: Is there any kind of preventative maintenance I can do in attempt to avoid this problem? or is this issue just sort of a 50/50 chance? I'm not experiencing any problems infact she idles and drives just fine, I was just not aware of this valve problem until I came across this video.
***** Regular decarbonization and fuel injector cleaner may help along with regular maintenance but mostly its just wait and pray. There is a problem with worn valve seats on some engines, it usually shows up very early, around 50k-100k. This one had a burnt valve which showed up around 120k. Typically if you make it past 150k your golden.
@@pfun41 Sweet - I made it past 150K - my idle is 600 rpm. I haven't checked for any oil on the sparkplugs - I don't even know what that means. haha. My mechanic did change the spark plugs and other stuff probably around 150K - and cleaned out the engine or something. I use MMO a big - had some nasty exhaust come out. I guess that can clog up the VVT though? hmmm. I'd like to get 500K out of this beast of a car. Like that Inline Six engine with the great torque.
On your video you take the intake & throttle body off. My question is how do you get to the last bolt by the firewall. What wrench, socket, etc. did you use. What is the tip/trick to getting that one out.
Need to use a 1/4 inch drive socket, on a universal joint, with about a 6 inch extension. Put painters (blue) tape around the universal so it can't "flop" down and you should be able to get it on there. The tape still allows some flex in the assembly.
Use a wobble to get it.
I got it out, but now I have a message that says 'reduced engine power'. do you know anything about that?
+Alex Rodriguez That's "limp home" mode. It does that to protect the drivetrain when it senses problems. Pull codes and see whats up.
how many bolts needs to be removed
auto zone said there's wouldn't clear codes...to be exact what do you mean get the VVT problem taken care of.
+jddllll Your codes indicate an issue with the variable valve timing, either the Cam phaser or exhaust cam actuator. This is the cause of your misfire and would be the first thing to take care of as it could potentially have something to do with the overheating as well. you can disconnect the battery to clear codes.
Any tips on getting all of these broken Head Bolts out? (Broke all 14!)
Get the head off. Drill a hole in them and use a screw extractor. The pieces usually come out easily once they've broken off.
when separating the block from engine did u have to release the tension from the chain? it seems like that part got skipped in the video
No. maintain tension on it at all times, if you let it get loose it will go out of time.
Can some one tell me where the oil pressure switch is located.
i cant seem to find the correct video
Please help,,,, how many bolts are there to get manifold out????????????? Ben working on truck for 8 hours and I'm tired but not willing to pay mechanic $400
David Viramontes 10. There is one hidden behind the tube in the center and one behind the alternator that are hard to spot.
Great job BTW, I think you have the only video on youtube doing this Engine! 4.2L I6 goes in all Trailblazers/Envoys from 2002 to 2009. And it's not a easy job by no means. What would be a decent cost to have this done on a 2004 TB? I just changed my Air Filter, gas filter, Cleaned the Throttle body. I have NO engine light on & in cylinder 3 & 4 the spark plugs had oil on them. This TB never miss fired yet. What would you do? I thought I'd just drive it until I get a light of some kind & then cheek out the problem. Help please?
New valve cover gasket is all you need.
Why you say only need a gasket I got a problem whith mine smokes only in higway at 70mph it let a blue smoke and yes it's leaking from valve. Covers
misael pacheco - do you have the 4.2 ? You shouldn't have valve "covers". It's a inline engine... just one cover. Is your engine only smoking from the dripping oil or do you have smoke from the exhaust too?
John Muller What did you have done to your engine I am having the same problem but with cylinder #2 any info would help thanks
these 4.2L engines are pieces of shit.
mine had only 90, 000km before it started burning oil like mad.
they should have been recalled by GM. it's crazy how GM got away with this piece of shit "engineering". the 4.2L engines are notorious for having shite valve seals. GM can go suck a big PENIS, I will never buy another one of their CRAPHOLE vehicles or any vehicle that bears its parts name. Their shitty transmission cooler line design is even worse, don't get me started on that. what kind of retarded engineers has GM been hiring for the past two decades?
i cant seem to get the intake manifold out and im positive i have undone all of the bolts. is there something im missing?
Is it very important to fix this problem?
What could go wrong if I just leave it be?
eventually it won't idle anymore and you could burn out the catalytic converter.
how did you get the intake off I'm having a hard time trying to get it off please help
there's a bolt under the hose
As fast as we live I don't know who can still do that if your job it's completely different than a mechanic. If I can get to that point on removing all that, maybe I won't put it back and I will toss the tools away. And call the scrap truck
What did it end up taking to get the broken head bolts out?
Brandon Arnold Drill bit and screw extracter. They break because of the tension on the bolt heads, the remains were actually almost loose in the block.
the tranz is dry could that be part of my problem ?
+jddllll no, but putting some fluid on the TC snout before putting it in wouldn't hurt.
Thank you for taking time to make this video, I am about to remove the valve cover to replace the gasket and would like to ask if you removed the coolant from the vehicle before you started filming or I can get away by just removing the bolt holding the houses and just moving them to the side long enough to get the valve cover off.
For just the valve cover it's not necessary.
Much appreciated...
wow i can get a motor with 82k for $900.my problems are over heating and missing.when i saw your video it sounded just like my problems. it has new radiator,thermostat.fan shroud,new fan clutch,,when i put the new radiator it ran good for two months.and now you can only go 5 minutes then it starts boiling over.if you turn the heat on it goes down for about 5 minutes then it sounds like the radiator is about to explode..i tried taking out thermostat it made things worse
+jddllll What about the solid state relay that controls the fan clutch? If that goes out it will overheat at a stop.
is it hard to change the head gasket
+jose nunez yep
Incredibly hard. This car was never made to be worked on again.
So doing it this way, you can leave the AC compressor? Don't have to recover freon?
Also, anything you would do different if you did this again?
I will be doing this soon on my girlfriend's 05. It overheated and the water pump blew. Replaced the water pump, but there's oil in the coolant. There's also been oil building up in the #3 cylinder for a while, so I think it's time to machine the head and replace the head gasket.
If you don't remove any ac lines you don't have to mess with the ac system.
How did you get out the last bolt on the intake manifold (closest to the firewall) off?
Need to use a 1/4 inch drive socket, on a universal joint, with about a 6 inch extension. Put painters (blue) tape around the universal so it can't "flop" down and you should be able to get it on there. The tape still allows some flex in the assembly.
HOW CAN I CONTACT YOU ? I need my truck fixed
what is the tool used to get head bolts off?
Breaker bar and I think it was a 10 mm hex drive.
Nevermind nothing wrong with the head it was one of those stupid pins that the rocker lays on
HOW MUCH WAS THE HEAD WORK JL
+jddllll $600
Good work, nice and detailed to the point.
A piece of portion fell in the motor
what bolt do you need to remove to get manifold lose?
+Alex Rodriguez Unbolt the PCM, remove the bracket underneith it. Remove the alternator,
there's a bolt for the intake manifold behind it that's hard to get to,
also pull off the tube in the middle of the manifold, there's a bolt
behind there too. The rest are easy to see, the one by the firewall is a
PITA. When you have it all unbolted it will come off easily, if it
won't move there's a bolt you missed.Don't try to get around removing
any of that stuff, you'll only make it more difficult.
+pfun41 how do you get the last bolt on intake its hard to get to no space at all even with swivle neck
wrench and lots of patients.
That's all complete pretty much now I have to set the timing chain with the cams then reassemble everything
137k new radiator .hoses ,thermostat .water pump ,,new plugs ,,map sensor.,,,will only cool down when you turn the heat on,,,that only last about a mile,,, the truck runs great after 2500 rpm
+jddllll Any trouble codes? What kind of coolant is in it?
WHEN THE OVER HEATING STARTED I ALSO LOST MY CRUISE CONTROL....JOHN
how do you get that intake out
nice
How do you manage to break that many head bolts? That plus the black crud all over cyl. #1 (at least that's all I saw there could be more), leads me to believe yours had a bad head gasket for quite awhile. The excessive heat could've weakened the bolts.. otherwise you're not doing something right. That could also explain the damage to your head. Just sayin'... Anyway, decent video no bullshit and straight to the point, just think you should've done a little more detail for everything you removed for people that aren't mechanics. Not bad though 9/10 stars I say...
You WILL break head bolts on the 4.2 Atlas. That's just the way they are. The 4.2 is known for excessive carbon buildup. Decarbs and throttle body cleaning are standard maintenance for these engines.
Yep I've further studied these and I concur... I currently have 2 vehicles with the same setup.
Absolutely a known problem with broken head bolts, PFUN did nothing wrong. GM actually now sells a special tool just for extracting the broken bolts.
Can you email or post a video of this in real time not fast forwarded plz having trouble taking off plastic intake manifold so i can change the valve cover gasket
sammy placencia I can't, the Video file for that part would amount to a few GB. You'll need to remove the PCM, There's a metal bracket under it that has to come out, its held on with a couple nuts. The alternator also has to come out. Once the alternator is out you should be able to see most of the bolts, there is one that's hidden behind the tube in the middle of the manifold. Once you get all the bolts loose it should pop right off, then just maneuver it out of there.
***** Thank you we got it the other day but we had issues how did you take off the last bolt closest to the firewall we couldnt get a tool in there so we just took off all the other ones and kinda pushed it aside and held it in place untill we could take off the valve cover
10 MM wrench, it's a tight fit.That Bolt is the worst one.
Mine just started doing a lot of tapping and a little belt squeal. Popped the hood and saw oil down the driver side, all the pulleys and noticeable power loss. Just hit 170k in the old girl. I knew she was about to shit the bed soon and boooooy in the middle of a road trip she did. I knew it was gonna be a valve. I don’t want to 😩😩😩
how many miles on this motor
Steven Nicastro At the time of this recording 144k. It's at about 150k now.
Awesome job, nice and clean
Hey man I have a gmc envoy 4.2 same truck I can not get the intake manifold out please help I have everything out the alto atop throttle body anything to possibly block it just seems to be like stuck in place
Please help asap thank you gladly appreciated
cameron duchene did you get the bolt behind the alternator out? There is also one behind a tube in the middle.
whats more of a pain in the arse, swapping engines or valve job??
Swapping engines. Do you really wanna mess with the front driveshaft in the oil pan?
the forth cylinder has water in it,,, you can shake the car and watch the water move
+jddllll Contunue with the leak down though it sounds like you have a blown head gasket. Are you shure it's water and not gasoline? if it is indeed water then safe bet the head gasket is blown, which explains all of you're problems.
you did a great job!good video I'm doing same thing on 04 envoy
Lets see I've replaced the fan clutch, soldered new instrument clusters then bought a new instrument panel now some of those are going bad, couple of speakers have blown, 3rd cylinder was leaking and was quoted an estimate of 2500-4000 from chevy dealership where vehicle was purchased but i got lucky with a totaled gmc with 80k on the 4.2l replaced with that and paid 400 for engine and 50k miles later 3rd cylinder came back to bite, a/c broke. If this isn't just a simple coil fix for 3rd cylinder I'm done wasting money, I love my car but I've got to find something else...good luck to anyone else who dares so this job or pull the motor it was a pain in my ass then and I'm not going through the same nightmare twice.
Premature valve seat wear problems affected the 4.2 up until 05. They redesigned the head for the 06 model year, which eliminated the valve problems and upped the compression a bit with a pcm tune to match. Older low mileage 4.2s are a gamble, valve problems usually show up by 100-150k if they're going to. When a certain engine has inherent internal issues I find it better to fix them rather than replace with a used unit, as they usually have the same problems later on. I'm dealing with a Dodge 4.7 right now.
I have a 2007 TB with just over 100,000 miles with the same problem so I am not convinced GM fixed the problem in 4.2L built after 2005.