How to diagnose a mystery coolant leak in a Chev/GM truck
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- Опубликовано: 28 июн 2018
- This is a short demonstration showing how I made the diagnosis and completed a repair of an occult coolant leak in a 2000 Chev Suburban. I pressurized the system and found the leak by carefully searching for the source of coolant loss. Pressure testing is a convenient way to find small leaks where no evident coolant loss is visible on general inspection.
Cooling system repairs can be dangerous, because superheated liquids under pressure will instantly boil and expand when pressure is relieved, causing explosion and severe burns that can be life threatening. Any misadventure you encounter if you decide to accept the risk of DIY repair is your responsibility. 
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Man i have a 2001 and I couldn't find where that leak was coming from and now you open my eyes I replaced the top hose even took out the thermostat I bought today a water heater but the leak is not near the water pump so it has to be your find thank u for your find....that made my day
I'm having the same issue with my LQ4 (2003 H2 Hummer). It's leaking from the same general area. Thank you for taking the time to put this video together. I will take a peak at mine and hopefully I have the same issue. Cheers!
Oh man, I almost bought an entire water pump system. Mine does leak and leaves a puddle and I just could not find the darn leak. I will check that later in the week. I went to Walmart and they told me I have an oil leak yet I have no oil on my driveway. This video is a major help.
Have me a 1996 Chevy c1500 centurion- had the same issue and felt like I was going crazy. Thank you so much sir! My Frankie will be fixed up in no time now. Don’t ever stop posting videos,you're one of the few that gets shit done. Thank you !
Determination and patience paid off. A pressure tester sure helps when looking for coolant system leaks. Well done.
Great video! Thank you for your time on finding that problem. I'm sure you saved a lot of people from wondering where that mysterious leak was coming from. Appreciate this video. Thank you!
Coolant is routed through the throttle body to prevent freezing of the throttle blade in cold climates.
Good point! I don't see an internal pathway around the throttle body but it wouldn't need much, given how close it is to the throttle butterfly.
rusco321 is right. Prevents ice formation at closed throttle at the butterfly plate. Old carbureter cars were famous for this problem even with heated intake air and or heated throttle bodies. More so when the temp is below 40 degrees F. with high humidity.
It's nice to find an easy one occasionally isn't it?
Your explanations are great. You don't skip ANY steps and even give us the nut driver size.
Thanks!
Yeah, I was due for an easy one, ha ha. Thank you for the kind words! On the contrary, when I make a video I usually wish I had worded some clips a little differently. At some point, you have to finish and move on to the next one. People are usually kind enough to overlook imperfections.
@@TaraConti Sounds like two fun challenges, likely unrelated. I made a playlist of cooling system problems you might find helpful. These days a leaking radiator would be high on the list for an obvious coolant leak. In any case, with an obvious puddle it should be easy to find the source. Good luck!
Great post!!, Exactly as what's been said earlier about the freezing prevention. My old BMW's ('80's E30 series) all have the same thing!
Very cool find Dave! Leaks are one of the few things in life you start from the top😎
I looked right where yours was dripping and was able to confirm that's where my was leaking from thank you very much for this very helpful 👍
I have been searching for the leak in my 05 silverado for 3 years been to the shop half a dozen times you have given me a good place to investigate thank you.
In addition to leak at that hose, this generation of the Vortec engine had a problem with porosity of their aluminum cylinder heads, leading to some developing tiny leaks through the head into the oil. I'm not sure about the 05, you might have a look at the cylinder head id number and the oil fill cap. Leaking there can cause a brown pudding forming on the inner side of the oil fill cap, although sometimes you can get a little pudding even in a normal car. Good luck!
Mine leaked into my engine oil and I ended up needling a new engine
Great video information. I've got a 2004 Yukon Denali an I've been having to add coolant a lil more than normal. You mentioned burping the system which was very informative. I'm gonna try this tomorrow for sure. Thanks
I need to get that tool to pressurize my system, I have the Exact same issue with mine currently. I didn't even know those hoses were there on the throttle body? Excellent video, I desperately was needing this!
Good catch, nice, informative. The 5.3L engine was used throughout the GM models but never saw a coolant connection being used on the throttle body!
I’m having the same issue with my 2000 GMC. No trace of a leak anywhere that I’ve found so far. I’m going to go right to this spot and see if that’s the culprit. Thank you so much for posting this !!
Hey did you check it out ? I’m gonna share this video with my mechanic.
@@ElleBrOw yep , we’ll I think it’s the main problem anyways. it was the water pump intermittently losing coolant out the weep hole. Just strange cuz it never left a puddle or trace. I caught it early. I’m hanging a new one on today.
This guy is very good. Just discovered this channel and subscribed.
Dude you rock !! I wish some of my teachers were as good as you.
Thanks! I have been fighting this leak for over a year.
I like your kind style. Thank you!
Thanks for your helpful videos, sir. One helped me replace the AC compressor idler clutch pulley on my Dodge truck, when bearing gave out.
I also dealt with a small coolant loss on said truck, losing about a cup full every few days. Pressure testing didn't reveal anything, but I used one of those block testers with the blue dye and it detected exhaust gases in the coolant. So now I was dealing with a tiny head gasket leak. This was further confirmed when I scoped the cylinders and found a tiny bit of coolant in cylinder #5 (4.7L V8 engine). I only noticed it because I was leaning heavily on the truck which shook it, and I saw the liquid move on top of the piston, on the very grainy video.
Well, the truck wasn't worth much and I was determined to do everything to not to have to pull the head gasket. Against my normal judgement, I used one of those block seal products, but used it very judiciously in a targeted manner, disconnecting the heater core during use and flushing out the radiator before it dried. Supposedly the stuff turns to glass and melted copper flakes as it encounters leakage in extremely hot places. I drove with it for many miles as initial application using the instructions did not work for such a tiny leak. Anyway, that was over 5 years ago and the truck now has 300,000 miles on it with no further loss. I later learned that Dodge coolant has silicates to prevent such leaks but I was using silicate free, so that might have contributed.
Thanks again for your videos.
Thanks for the followup, you made my day!
Good find. Pressure testing on a cold engine makes things much easier.
I'm dealing with this problem now, I bought a hose barb connector and bypassed my throttle body all together, good video sir👍
I have a 03 gmc truck and you explained exactly my problem. It's driving me crazy trying to find it. I'm going to check it tomorrow and I bet that's my problem
Thanks Alot.
Any update?
And I believe the hose on the right of the throttle body is the one that goes to the steam crossover lines that run under the intake manifold.
Great video Dave and I can see how that tiny leak would be hard to find. I suspect that the coolant passing through the throttle body is to help the fuel vaporize during the winter months. Good work!
I love reading discussion threads like this, they usually add something that brings color to the video. Thanks for making it worth reading!
I doubt it since that engine is fuel injected.
Thankyou that is exactly what my problem was you hit it on the head and saved me headaches
Thanks for making this video very HELPFUL 👍🏽👍🏽.
Thanks for the info, now I have a place to start looking 👍🏼
Thanks for posting. My truck seems to have the same issue. I checked and the block looks clean so I'm sure that's the problem.
I’m having that same problem thank you for this video I never knew about those hoses.
Thanks for the video.. My 2000 Silverado is always in need of fluid but thankfully Never ran hot.. I do hope this why I keep loosing fluid and seeing no leaks in my oil or anywhere..Thanks a bunch for this information👍👍
Thanks for the sub, man!
Leonard was this your problem after all? My 06 silverado is doing the same. Never goes hot and I'm constantly filling up on coolant but never spotted a leak
This was a great video and very helpful
Great vid, as always. Glad it was a no-cost fix!
Yeah, always the best kind. Without the pressure tester to identify where the water was coming from, one might have been led to the misleading conclusion that the water pump gasket was bad. I wonder how many water pumps are replaced on these vehicles when the real culprit is a leaking hose above.
Agreed! I need to get one of those. I heard you say it was an Astro, do you have the model number? Thank you!
I bought it about a decade ago, Astro 7858. Less expensive alternatives are out there, especially if you only need it for one vehicle. Also I believe some parts stores will loan equipment. Stant offer the core device on Amazon for much cheaper, then you buy the exact adapter for your vehicle separately. And I'm sure Harbor freight will offer something similar. I maintain a small fleet of vehicles so I wanted a kit that works for several models. The other option is to disconnect a hose in the system, then use rubber corks to jury rig an adapter to pressure test from the hose. Of course there is also the option to just run the vehicle to pressurize with the water pump, then carefully inspect. In that case you've got to avoid spinning belts and hot coolant that will boil over when you start the repair phase. I invest in tools with money saved from doing this myself, so in the end the main benefit of home repair is not financial. Insight gained from learning how these systems work is priceless.
Very interesting. Thank you for sharing
I need to find a small coolant leak in 2003 Chevy Cavalier. It is dripping from the right side below. Thank you for pointing the possible locations of the leak, like by the throttle body hoses, and how to use the Coolant Pressure Tester.
Check your heater core connections. When you say right side I’m assuming you mean passenger side. That’s where your heater core connections is located. Also check the floor inside on passenger side to see if it’s the heater core itself leaking.
Super helpful. I'm gonna check there first because after watching this I think mine is the same. Just got the sub button so I don't miss any more helpful videos. 👍👍
Thanks, nice to meet you.
Dave
Thanks for this video my dad yukon has the coolant smell but the main hoses are dry I will be looking at these hoses today thanks
same here today! Any updates on what you found?
love your problems, cause they match my problems and the coolant checker is like mine as well, turns out my seep holes are leaking on my water pump ever so slightly, could not find it otherwise.. Slant coolant checker would have cost us way more , great diagnostic tool here.. and awesome video as always...
Thanks, man! The one thing my kit is missing is a cap tester, though testing the low pressure valve in the cap can be done easily with no tools. Most cap problems are at the seal, easy to inspect, anyway. When I look back, cooling system problems and battery problems are the core of DIY auto repair. If you understand those, you can cope with the vast majority of auto repair problems.
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@@spelunkerd i ended up having to make my own cap inspector for this kit, still great price and offerings overall..
Love the systematic approach you take. Obviously starting with the right tools and a clear understanding of engine cooling helps.
Would love to see a similar vid about finding / repairing a refrigerant leak in a marine bar freezer. Most specifically a NovaCool F1900, but any bar fridge / freezer with 134a refrigerant in it should be roughly the same process I would think.
There are some very good videos on 12V A/C systems here on RUclips. For an excellent A/C review, search the RatchetsandWrenches channel, he's a good teacher. It took me a while to find the adjustment dial for the fridge cooler on our boat, it is hidden in a very dark corner of the pantry cabinet. I was sure glad to find it before asking my brother, an AC tech, to help me out. He would never have let me live that one down, (grin).
Great find
I have the same issue on this 99 suburban, just replaced water pump, thermostat and housing, radiator and upper and lower hoses. Left in garage for 3 days with cardboard under the suburban. I am gonna check this now. Thanks
Did you figure it out??
Great job man
pretty awesome. And yes Throttle body is not even mention in the diagnostic. it's always the intake manifold.
I did a little research on that. The LS engine series had a coolant air bypass system that was designed to clear air pockets from all four corners of the engine waterjacket and send them back to the radiator and coolant reservoir. It was added to the design to prevent localized overheating. It also makes burping air from the system easy. In my engine you can see ~1/4" steel coolant pipes above the valley between the heads and below the intake manofold on my LM7 variant, and on other engines of this vintage. Those tubes merge together into one hose that goes to the throttle body, so that any ice in the throttle body would quickly melt. From there coolant is sent along the tubing that was leaking in this video, to arrive at a midpoint of the radiator on the right side. When Chev decided to add their notorious displacement on demand system, they deleted those pipes. Some guys modify those pipes to use braided hose, you can buy specialty tubing kits to do that.
NICE! Happy I found this. I have a mystery leak on a 2000 gmc with the 5.3. I recently had the throttle body off for cleaning, and at the time was cursing those small hoses. Today am under the truck fixing of the stuff and notice a small/slight coolant leak dripping from the front of the engine. I know exactly where I am going to look tomorrow. 👍
If you can't see leakage with engine running where mine was leaking, you'll need to get a closer look from underneath. Pay close attention to the radiator, which commonly leaks where plastic meets the aluminum heat exchanger. To inspect properly underneath you'll want jack stands (not just a jack). You'll need to remove the skid plate that is bolted on and plastic covers. Then when engine is not running crawl underneath and find the water pump. A common source of leak is the weep hole from the water pump. I did a whole series of videos on your engine, and I have a playlist of cooling system problems on my channel you might find useful. Many demonstrations were done on your engine. Good luck!
Thanks. It looks like it is leaking from the water pump to block gasket, on drivers side near the power steering pump. So the dilemma I have now is do I go with a whole new pump or just replace the gaskets. I will look for your other content on this one. Great quality content videos by the way. Very professional. 👍
@@billybobbarker3175 As I recall, I did a two part video set of this exact many repair years ago, it was about 2013. Content delivery is a little slow in those old videos but the information is there. Back in about 2020 I had the same leakage where you describe and I did the repair again off camera. It's been fine ever since, I drove it yesterday.
Oh, one more thing. When I first did this water pump in 2013 I came down heavily on the side of replacing the pump at the same time, which is a work pattern followed by most pros. Given the poor quality of the last remanufactured pump I got from NAPA in about 2020, I've been rethinking that bias. Even the weep hole on that reman pump was covered over with paint. At that time I got better gaskets separately so I didn't have to use the thin paper gaskets that came with the pump. So, it might be an idea to replace only the gaskets, they were easily available at that time. Pros don't do that because they don't want to warranty the labor, but in amateur work flow the cost of labor isn't very high, ha ha.
@@spelunkerd Exactly my thoughts. I picked up a pressure cap for testing. Will try that in an hour or two, and go from there. I hope/plan on just the gaskets and resealing the backing plate of the pump, assuming that is the leak area. Even though it is old and probably original, I have no bias or want to replace the pump if it is not showing anything from the weep hole. Circulation is good, heater blows hot, and pump turns smoothly. Just a seepage and small daily drip to find and fix. The truck has 238,000 Km. Thanks a lot for the thoughts and encouragement.
I think you may have helped me find my mystery leak. Thank you so much.
It wasn't where my leak was, but it pointed me in the right direction. Either way it helped.
Where was your leak? I’m currently trying to find mine
Thank you for your time
Great job!
Great information. Thanks.
Liked & Subbed!
Awesome, very observant
mine was a faulty leaking water pump seal. it only leaked when driving under pressure
I found your video helpful simple and easy to follow
Thanks! I’ve been wondering about my leak for years. It’s ever so slight if a leak but enough to make you or the wife worry. Same thing, no evidence of leaking anywhere but a slight smell of the coolant fluid was a give away. Seems the video was proof of where my leak was. Again thanks so much!
Common leaks come from the water pump seal or weep hole, hoses, sometimes the radiator or heater core, rarely a head gasket. This LM7 5.3 engine also occasionally had a notoriously slow leak coming from porosity of the head itself. Hopefully your solution will be more simple, good luck!
@@spelunkerd
Even more helpful information. Again appreciate it!!
Very good video.. I get a strong smell of antifreeze on my 06 tahoe after engine has been running for a while.
Although it doesn’t overheat I will be checking that next..
If you can smell it in the cab, check the floor mats, it is probably a leaking heater core. The one other thing that can cause wet floor mats in some vehicles is the drain for the AC evaporator, which can get plugged with dirt and cause overflow, but that is just water, not coolant. Heater core removal is a pain because of all the plastic you need to remove to get at the coil. Good luck!
Thanks for your advise.. I will be checking the hose under the throttle body next.. since the passenger floor board is not wet and you can only smell the antifreeze when you descend the vehicle after it has being running for quite some time.. thanks
Really good info, thanks
Thank you for a very helpful video for us rookies.
I thought it was the damn head gasket until I saw this video. I’ll be checking it tonight Mahalo.
I will check this out on my 5.3!
Heated coolant is routed thru the throttle body to prevent freeze up during cold, humid weather driving. Older engines used exhaust heat to prevent freeze up.
Hmmm, … I have this problem. Your explanation makes me wonder …. Since I live in Southern California very dry and mild …. Would it be reasonable to bypass the coolant flow through the throttle? Just a thought; first I’ll try fixing it.
Nice job .
Thanks, man! When I discovered I have 706 heads, I was wondering about bigger problems. Fortunately this one was a simple fix.
well done.
Well that was a sneaky leak, very hard to detect without your pump up tool.
You have some rubbish vehicles, they are always breaking down LOL :-D :-D Joking.
Hi I'm Roger the Farmer from Grantsburg Wisconsin ! I just found this in my feeds and have a 2000 Tahoe that I picked up from a kid who had it for about a month and smoked a Deer with it . It took the Grill ,lights , condenser, Radiator, coolers , fan , the whole front all most . I got it from him for 400.00 Buck's ! Bucks ! Lol Any way got all the parts for about 300.Bucks put all together and has been on the road about 6 month s and I started to drop COOLANT . I do have dash issues with the lights blinking on and off and Service 4wd light on all the time . And one I can't figure out .
When I turn on the key it's always in 4hi . I have to push it to Auto 4wd then to 2hi with the transmission in neutral and push the button s a couple of times and then it will go to 2hi and the indicator light goes out and it's in 2hi . As soon as I turn the key off it defaults back to 4hi and I have to do it all over again every time the key is TURNED off ? Help I don't get it. I'm a Allis Chalmers Tractor guy not a GM Tech support guy ! Lol . I'm going to check out my hoses about the coolant and see if that's the case I have or they said it might be a cracked head too . I hope not. Thanks I hope you get this email
The transfer case switch that controls the FWD in these vehicles can go bad, which could cause what you describe. Also with all the front end damage you might have a look at the shift motor on the front axle, responsible for locking the two front hubs together. It is electrically controlled, you want to be sure those wires are intact. I'd check the fluids in both the front axle and also the transfer case. You may get more info from a high end scan tool. The transfer case in these vehicles has three VR speed sensors that help the transfer case do its thing, and if one goes bad it may interfere with shift control. I did a couple of videos of that problem in this vehicle. I also did a series of videos showing repairs of this Suburban over the years, including a few showing how to investigate a slow coolant leak. These vehicles were prone to a couple of things. The NVG246 transfer case was vulnerable to 'pump rub' causing catastrophic oil leaks, and also the cylinder heads were prone to porosity that sometimes caused a slow coolant leak. Neither of those happened to mine, yet.
Love your videos, very educational, fun, and informative
Thanks!
Thanks, helped with my '04 Suburban. Totally redoing my Suburban. Why Pay $80K for the new junk their selling today.
Outstanding!!!
Thank you! Cheers!
A quick tip when removing those hoses under the throttle body use some small vicecreap ply iré to prevent from loosing to much coolant..
Good point. I have a set of small needle nose vice grips with rubber hose on the ends so that rubber tubing doesn't get damages when crimped. Honestly I didn't expect this one to drain much, it drained more than I expected.
Extremely helpful, especially the 2 intake/throttle body hoses that are left unmentioned in repair manuals........
Nice find! I have this symptom. Also I smell coolant when I come to a stop.
If you smell coolant in the cab of the vehicle, check the floor mat on the passenger side for wetness. The heater core is a type of radiator that can leak coolant and give a moist smell. Unfortunately it can be hard to reach, labor to replace a heater core can be significant.
جيد احسنت استخدمت الضاغط بشكل رائع
Thanks!
He say's "Well done well compressor was great" (google translate)
I would agree
Had a leak forever good tip
GOD BLESS YOU MR THANK YOU THANK YOU THANK YOU SOOOOO MUCH. dude you found my leak that I've been chasing for a while 😆 THANK YOU SO MUCH GOD BLESS
My friend the hot coolant flows through the throttle body to prevent icing due to the temperature drop from the Venturi, Bernoulli’s principle states that when you move a mass of air or a fluid through a Venturi two things need to happen number one the temperature must drop number to the pressure also drops
Excellent point! It is so nice to find your remark, one that inspires deeper thought.
I wonder if a spring clamp might be a better choice. Perhaps hose deterioration allowed worm gear clamp to lose pre-load. good video.
Yes, now that you mention it, I agree that spring clamps seem to do a better job for these small diameter tubes. I find the spiral threaded clamps on small tubes tend to dislocate and not give as much tension as I would like. Also this tubing is plenty strong and it doesn't kink but it is not very flexible. The next time I visit the parts store I'm going to pick up a few some smaller diameter spring clamps.
I replaced the water pump in my 2002 GMC Envoy about 4 months ago, and just recently started smelling coolant when I turn the vehicle off. Where do you suggest purchasing a pressure tester?
Harbor Freight, Amazon, Princess Auto, Ebay, many auto parts stores. The adapter kit is fairly important since it needs to be versatile enough to fit many vehicles. If you smell coolant inside the cab, feel the carpets for wetness, especially on the passenger side. A heater core replacement is a big job, hopefully not. I would have liked a cap tester to verify the pressure needed to open both the cap valves. My kit doesn't have one of those. If you smell coolant around the water pump, try to get a look at the weep hole from underneath.
Hi Dave....another great video. Honda runs coolant through the throttle bodies to try and eliminate icing of the butterfly valve in cold weather.......I suspect Chevy is doing the same thing here.
Excellent thought, Nick, others said the same. Terry suggested it is to help fuel vaporize fuel in the winter, which is a variant on the same theme. People don't remember how difficult it was to start carbureted vehicles in the winter a generation ago. It was always a question as to whether one would get to work on time. Thanks for making this thread worth reading!
Not only the butterfly valve but maybe freezing in the throttle due to the Venturi effect I believe. Great video have to keep this in mind for my similiar 03 Suburban. Clean those leaves out of the hood! My pet peeve! 😁 thanks for video!
Said hoses are to keep throttle body from freezing up the throttle plate in humid freezing temperatures.
Thanks
My 2001 4.8 has a mystery leak. It would be so nice if it was a hose and not a head gasket. Next, get my hands on a pressure tester. Thanks for the vid.
I'm told that some autoparts stores will loan them out for a deposit. This version of the GM engine has an unusual sized cap and it can be hard to find the right adapter. The other option is to find an inexpensive generic kit online.
After water pump replacement (suddenly it started severely leaking at the main shaft) I am loosing slowly coolant. I can smell something strange after several straight in a row WOT (wide open throttle) acceleration on my 2000 Tahoe. Where shall I start looking?
If a new problem develops after working on the car, most of the time it can be traced to something you did. I'd be checking to be sure I didn't put the pump on with a fold in the gasket or gasket malposition. Even a piece of grit might be enough to cause the pump to go on cockeyed and leak after, and sometimes if you don't bolt the pump on with a cross pattern it will not cinch down evenly. Remember to hook up both hoses that attach to the undersurface of the throttle body. I would inspect looking for coolant leak out the weep hole, try to identify where it is coming from. A coolant pressure tester helps find microscopic leaks, some parts stores will loan them out. It isn't uncommon for pressurized coolant recovery tanks to leak, they are made of plastic. Also watch out for a bad seal at the cap, if it won't seal the system won't form enough pressure to work and you'll slowly lose fluid in the form of condensing steam. Regarding your point about odor after WOT, a head gasket leak can present in that way, and a previous overheat might be enough to blow a head gasket. Let's hope it is not that. Look for brown pudding under the oil fill cap, and look for steam out the tailpipe. The Chev 5.3 Vortec had an issue with cracked heads, but that wouldn't usually give odor after WOT. Odor is sometimes found with a leak at the heater core, check for wetness on the passenger side floor mats.
I have a 2004 we hitch is losing coolant and I have already changed the reservoir cap recently. What else could it be and should I do a pressure test? If so can I rent or do one at autozone?
Some autoparts stores will rent equipment like that out. In the meantime, check the radiator, coolant reservoir and all the hose fittings carefully, looking for a wet spot. Sometimes you only see discolored crusty residue around a slowly leaking component, such as the plastic coolant hose flange in the Jetta, a notoriously common problem. Don't forget to look underneath the water pump for the weep hole, if it is leaking there you need a water pump. If the cab is unusually damp or smells of coolant, it could be the cab heater core. Usually if it is more serious like a head gasket you'll have other issues, such as white smoke out the exhaust or recurrent overheating even when coolant is well topped up. Occasionally I've had vehicles that don't show me the diagnosis, in which case I top up the coolant frequently and wait for more clear signs to evolve. Don't be tempted to use StopLeak, those compounds cause more problems than they solve. Good luck!
Hi, I have a 2016 chevy silverado 1500. I have a slow "mystery" coolant leak that takes about 2-3 days after I've refilled the coolant for it to start overheating. I can't really tell where the leak is coming from with all the emissions crap covering everything. It is wet all along the bottom part of the radiator and a very slow 1 drop every 5 min off the framing behind the headlights. I dont see wetness anywhere else. Radiator leak? things I should check first? Loved this video. I'm gonna start watching your other videos right now lol. oh miliage...130,000
Take off the plastic covers underneath and find out where that leak is coming from. Lots easier if it isn't raining outside, ha ha. The most common cause of a leak at the bottom of the rad itself is the radiator, which commonly leaks from the two plastic end caps, one on each side. Other places to look for are hose connections, the weep hole of the water pump, and various connections including the drain spigot at the bottom of some radiators. If the rad is leaking, simply replace it, nobody fixes those any more. Keep the reservoir full and don't delay repair.
thanks
I loaned one of these from my local advanced auto and none of the caps fit my radiator so used one of the universal ones the kit came with. The system held steady at 15psi the whole time and I couldn’t see any obvious leaks. Pretty annoying I know I have a leak as I always see it dripping around the transmission and have a small pool under the truck. Oh well..
I have the 05 Tahoe 5.3 (250k miles). Every time I fix a leak a new one arrives. Current leak is closer to the driver side right near the firewall. I tried for awhile with a mirror and light but could not find it.
Had this issue with an old van and it turned out the radiator was 90% clogged and the high pressure was blowing the coolant system all over.
tanks
Cool thanks
That is the design they built for the cold climate these trucks are built in canada so it is warm water to keep the trottle body to peform like it should in the weather up in the northern states ....
Chevy 8.1 Liter Vortec in my 2003 Suburban does not have this tiny hose.
Gonna have to check there
Ive got a sloshing sound now from my passenger side dashboard i have a feeling i have a bad heatercore 01 Tahoe 200k miles
And yes they pressure tested it last year!
Yeah possible. Any cause of trapped air will do this, always start with burping and checking seals, hoses. I did another video of a mystery leak in my Dodge Ram. Turned out to be a pinhole hose leak in one of the heater core hoses, very hard to find. Good luck!
I just got an '05 Silverado 2500HD last week. When I got it home, during a system checkout, I found I had no heat. That turned out to be low coolant. I added a gallon of antifreeze and the heat worked fine.
The thing that concerns me now is that I'm seeing excessive steam from the exhaust and there's a sickening sweet odor, not quite your normal cat converter smell. That has me thinking that the engine may have a head gasket problem and that I should contact the seller and let him know there may be a serious problem.
35 years ago, I had a head gasket leak on a '69 Buick Riviera and the engine grenaded while on the highway, utterly destroying it totally. It turned out to be a head gasket leak responsible for the piston hydrolocking. I just got this truck and now I'm concerned it may be a few miles away from a major catastrophic failure if I drive it.
Gotta wonder how much the seller knew, it is hard to ignore a persistent coolant leak.
@@spelunkerd Well I got the truck registered today ($445.09!! not including sales tax!!) and drove it to a couple of places. No steam out the exhaust. Now I'm thinking it was the low dew point and near 100% humidity that was creating an unusual exhaust condensation condition as I had a big cloud of what seemed to be steam lingering around the back of the truck last night. Today, nothing. But there is a smell of antifreeze near the engine compartment, so there is a leak somewhere. Just how much, I don't know.
But the radiator hose was not hard or under pressure this morning when I checked it, so that's a good sign.
@@basspig Good. You might have a look under the oil cap, condensation there is common and some of the earlier models of this truck had issues with head cracking/porosity.
@@spelunkerd Oil looks fine, no white foaming or other unusual stuff. Looks freshly changed, but prior owner says it's got 2000 miles on that oil.
Same goes for the tranny fluid. Clear pink, like just changed.
Truck runs great. But there is a coolant leak somewhere. It loses a noticeable amount every day.
Does this one have the ls or the previous generation small block Vortech?
They were still using both during those years
Good question, I find this topic confusing, even after reading an extensive Wikipedia article on the LS GM small block engine. My engine has the letter 'T' in the eighth position, which labels the engine as the LM7 variant of the 5.3, a subtype of the Generation III Chev small block. As you know there were many LS variants. Reading through that article, GM routed coolant through the throttle body to warm incoming air to promote fuel atomization during cold weather in early versions of their small block. Later editions discarded that innovation because of coolant leaks and because modern fuel injectors don't rely so much on warm air for atomization, and also because warm air has a lower oxygen density. Thanks for stopping by!
@@spelunkerd Thx. If yours is the 4.8 or 5.3 or 6.0 then it is an LS for sure.
However they were still putting some previous generation 350 cubic inch or 5.7 in those in the late 90s and early 2000s and I believe they made a 5.7 LS aswell but I'm not sure if that was only in the Corvette or they also put that in the trucks
Looks like someone has been there before. Hose clamps are not original. I truly thought the leak was going to come from the intake manifold. Nice job as always
Yes, that was me, when I swapped the water pump five years ago I replaced those hoses. As the original owner, and the only mechanic who has worked on this vehicle, I've got nobody to blame but myself if I do something wrong, ha ha. Thanks for watching, Richard!
Hi I have a 2003 chevy avalanche I keep feeling coolant ofter and it's coming out from the bottom under my truck or it cold be a bad leak what do you think sir
If it is coolant on the pavement rather than just water from the AC system, you've got a major clue that will make it easy to find the source. Common causes are a cracked radiator, leaking hose, or a failing water pump seal or bad radiator cap. The critical thing is that you keep the fluid level up while working it up, since ignoring it could overheat and kill your engine. I would have a close look in the next day, and I would make every effort to get this diagnosed within a week. Repair for the above problems is not usually very expensive, so unless you really want to pursue a DIY approach you're probably better off getting pro advice. I did a whole playlist of cooling system problems if you want to go through the effort to learn more. Good luck!
Hello nice video. I assume that is a v8. My v6 is losing water but i dont think it has this hose. I imagine it is the head gasket
I add coolant every month.
This vintage of truck is also prone to porosity of the metal used to cast the heads. The casting number on the head will help decide how likely porosity is. My casting number is 706, easily seen on either side by wiping grease off the top of the head (front on passenger side, rear on drivers side). If you don't find a cause with pressure testing, and you have a head that is vulnerable to porosity, consider removing the rocker covers and repeat the pressure test. On the other hand, more common causes like a leaking radiator, water pump gasket, or hose are still more likely.
I had the same issue and discovered right where the thermostat joints into the antifreeze tank and heater hose that plastic joint with those plastic or rubber clamp that plastic joint had a hair line Crack in it , also it had become dry rot I'm buying a metal joint to join those 3hose together Sound like they where trying to save money and cut cost you ask me
As stated in remarks below, coolant warms the throttle body to get sensors and the throttle plate warming quickly. I've been looking for a good explanation for why this LM7 variant of the Vortec engine has crossover piping that ultimately sends coolant/steam to the throttle body, then back to the rad. Chev abandoned those crossover pipes in later years. For a good video explanation of why these 'steam pipes' are there, try this RUclips video ruclips.net/video/e2_twsAziZ0/видео.html. It explains a lot, also including remarks about the unusual design of the thermostat and water pump.
I'm late to this video but the cooling is probably because on the earlier models of the LS style engines there was EGR that was plumbed back into the intake at the throttle body. On later models ~2005(?) on up, the EGR was deleted by the GM engineers, obviously not needed hence the cooling bypassed the throttle body.
@@stevea6722 That's an interesting thought!
What would the name be or part number
I will check mine tomorrow, I have a mystery leak on an ‘05 Tahoe.
Did you find the leak?
I’m loosing pressure in my 05 Tahoe and boiling over my resovior I can’t find the leak anywhere
@@Andrew-B_eZ Could it be a blockage? I keep having leaks on my 05 Tahoe, I’m starting to wonder if I have a partial blockage. I have to do the intake gasket next.
Radiator
Same issue 2002 silverado. No overheating, coolant smell, coolant loss in resavior, and 102k miles.
If the smell of coolant is present in the cab, check the floor mats for wetness that might be found if the heater core were leaking.