I have two of these engines. One of them is now an 8.8. Once you replace the low tension piston rings thereby preventing oil consumption it is a wonderful engine.
I heard or read somewhere, that forged pistons are used in these 8.1L. The expansion rate is rather slow during the heating up to normal temperature and this causes excess blowby. It would explain why some people need to add a quart every 2000 miles and others longer before adding oil. The ones adding oil frequently probably drive relatively short distances. The pistons may not have expanded during most trips eating up oil. 🤔 🙄 🤷🏼♂️ The low tension rings? Are you talking about too big of a ring gap from the factory? The oil control rings or both control and compression rings? Maybe the steel used in the rings you're talking about is flimsy. They might purposely leave a big ring gap for the expansion and that would cause the oil issue. It just takes longer for forged metal to adjust to temperature expansion, I suppose.
02 GMC 2500HD w/8.1 vortex and allison transmission - 4.10 gears. Bought it new and now has 325k miles on it. I love this truck! Used 2 quarts of oil aright off the lot...dealer said its normal until I pressed the issue. Turned out there was a bulletin on the intake manifold gasket causing oil consumption. After that, 1 quart every 3k miles. Crank position sensor replaced at 50k and 275k. Besides that, all I've had to do is regular maintenance, 2 fuel pumps, and a water pump. I suspect I've got a couple broken exhaust manifold bolts and the AC (totally original-never charged) is acting up. Blows 37 degrees F at the start and then cuts off after 15 mins of driving. I might add that half the total miles driven are towing miles!
Thanks for the info Jake. I own a 2002 Silverado 2500hd 8.1 backed to an Allison 1000, one of the best combos, 274,569 miles, running strong to. I've owned it since 2003 and knock on wood I have only have the issue with the Crank Position Sensor a couple of times and a little oil consumption. This weekend I am rebuilding the original front suspension with all new parts. Thanks again.
@@wesleybryant7334 Thats a tough choice. I would ask for maintenance records and look under the truck for leaks and rust. If the truck was maintained and taken care of it should be a good buy for the right price.
@@Toddderose they’re asking 15k seems to be well taken care or only thing is I can’t physically look at it because it’s online and too far to travel and check it out. But there does seem it could have a little corrosion underneath.
I own 3 GM vehicles from this generation: A 2005 Suburban 2500 (8.1), a 2002 Silverado 1500, and - the crown jewel - a 2004 Hummer H2 Luxury package. I bought the Suburban with 110k miles (it currently has 210k), the Silverado with 137k (it currently has 179k), and the Hummer with 53k (it currently has 79k). I daily drive all three, and have done many long-distance road trips and family outings in both the Suburban and the Hummer. I occasionally tow with all three (nothing very heavy), and have done a fair amount of light off-roading with the Suburban and the Hummer. These three vehicles have proven to be the toughest, and most reliable vehicles I have ever owned by FAR, in my total 35-ish years of vehicle ownership. In the case of the Suburban, also the most versatile and useful. GM really knocked it out of the park in the early 2000's.
The oil consumption issue is courtesy of the general's engineering. They put the crankcase ventilation valve in the bottom of the intake manifold where it literally ducks oil out of the lifter valley. Lawrence Tollman addresses this issue on his channel.
I've had an 8.1 for just over 10 years now and wouldn't trade it for anything made today. It's in a k2500 Suburban with a 4L80E, a full floater 14 bolt rear end and 4:10 gears. It has 340,000 miles on it and it goes through a quart of oil between changes at 3-4K miles. I put E3 plugs in it with a set of 8MM plug wires from JBA headers and haven't had a plug go bad in over 25K miles.
Tbh the best gas engine GM has ever used in a heady duty application… don’t forget the exhaust manifold bolts like to break and annoy you. But tbh, that’s a common problem on almost every truck in the early to mid 2000s.
Yeah but it is so crazy prevalent it probably should have been included. I am looking at at least one snapped off manifold bolt now actually on our 2001.
I have a 2003 Sierra 2500HD 8.1 gasoline that had starting issues. It would never start on first crank, would backfire while cranking but would fire up around the third crank attempt. I replaced the crankshaft sensor, camshaft sensor with no improvements. After a year of dealing with it I came across a post on a blog where they were having the same issues. He said he swapped out the timing cover and camshaft sensor with the updated 2004 version and it fixed the problem. I decided to give it a try, also got new timing chain and sprocket while I was at it and sure enough it fixed it and haven’t had an issue since.
Great video. I found a low mile 8.1 silverado in arizona couple years ago. Regular maintenance and it runs awesome. Love mine. Put in a true dual 3in exhaust with xpipe, no muffler, stock cats. Sounds better than my jeep that has a 6.0 LS. Great trucks!!! Ive only had little/easy repairs - ac leak, hydro booster, blend door actuator and the usual suspension components wearing out. I am very anal on maintenance but i enjoy it as these trucks are easy to work on and find parts for.
We had a 2001 Silverado 3500 8.1 with 4.11 gears for 10 years. Got 8.5 MPG towing our 5th wheel. Now driving a 2022 F350 dually 7.3 Godzilla with 4:30 gears. Gets 7.5 MPG towing the same 5th wheel. However, it will maintain speed up the long hills, unlike the lower HP and less tranny gearing of the 8.1
Experiencing the same had an 8.1 with 4:10's for 20 years got 300,000 miles out of it. Got a 22 7.3 with 4:30's also and I swear the gas mileage is worse than the 8.1. You're right about the horsepower difference its almost 100hp more and you can feel it but dang I was hoping the 10speed would help more with mpg's tho.
We have a 2001 Suburban 8.1 Vortec.... still at 187,000 Miles. We will NEVER get rid of it. We don't drive it as much, we all know they have a huge fuel appetite...😂 We love it.
You obviously haven't worked in on 8.1 engines. The claims of spark plug failure and lifter tick being "oil consumption" issues is something as a GM master tech I have never heard. The actual issue with lifter tick is directly caused by lack of oil changes and poor quality oil. The spark plugs were originally gapped at .060 and there's a GM service bulletin that updates the plugs to a iridium tip plug with .040 gap. This update solves a starting issue in some spplications in cold weather and is said to improve fuel mileage. I have never heard of plugs failing due to oil consumption and "contamination". Maybe on a poorly maintained high mileage engine but certainly not a normal condition. The plugs generally last 100k without issues. The 8.1 has a cast aluminum intake manifold and is not know for intake gasket failures. This is a common failure in the small block 4.8 -6.2 liter V8s due to the incredibly cheap plastic intake manifolds and the extremely light torque spec for intake bolts. This is not an issue on the cast aluminum intake. The oil consumption issue is directly related to piston skirt design and is common to all late model GM engines. The 8.1 engine has very few issues and GM engineers designed the engine for a 200,000 mile service life. The critical issue is use only high quality synthetic oil and change at 3,000 mile intervals. Lifter tick due to poor oil quality is corrected by adding Riselone High mileage oil treatment. This additive will clear the lifter issues.
With a 120k mile 8100, getting a off beat knock. Oil pressure needle vibrates and just over 40psi. Runs smooth, started after sitting 2 years because afraid of the knock. Need a trick to diagnose w/o ripping out. 20w-50 will try first
I have not heard of a lot of these - but the 8.1 in my Avalanche had a camshaft lobe failure. Spalling on the tip of the lobe until it lost enough height to cause a lifter click at higher rpm. However, after replacement at 107,000 it has been fine and is now at 203,000.
I just replaced my spark plugs for the first time. Kind of embarrasing for 301000 miles. They looked perfect. Didn't even need changing. I have replaced the radiator, water pump, hydro boost for brakes and the crank position sensor and all the obviuos brake, bearings,and front suspension. Still same transmission with no service besides flushes. The most reliable engine I have had in 40plus years as a mechanic. And still fun to blow away average vehicles off the line with 455 lbs of torque
Only problem I ever had with mine was when I went through a phase of using 93 octane fuel. The plugs DO NOT like that. Keep it to 87 octane, change your oil regularly and it's a beautiful platform.
I love mine i have a 8.1 i bought in San Diego for 6000 from original owner this will be a lifetime ride and it is just amazing bought it with 140000 and now has 143000 best investment ive made in years
The only problems I have had since 2001 was oil consumption but switched to royal purple 10w 30 synthetic , intake manifold bolts come loose do to vibration and replace crankshaft position sensor and a mass air flow sensor other than that it’s a solid truck zero rust starts every-time just keep the maintenance no problems also upgraded brake lines and brake systems to stainless steel and new stainless steel fuel lines and a fuel pump but she never says no or ever stranded me
I have a 2005 crew cab with 8.1 and Allison that I bought new. Only problem I ever had was the gauge cluster and driver door latch. Did the transfer case pump rub fix early.
@@8020Media thanks for responding anyways, I’ve decided to get rid of my cats, and straight pipe to a FM delta series 50. If you’re interested in hearing it I’ll post a video.
@benzoil0453 in trucks 2500 3500 its in until beginning of 2007. 4500 5500 6500 7500 8500 it was available in koadiak until 2009 last year gm produced medium duty trucks
A lot of it has to do with big blocks running forged pistons and it takes a while for them to expand. In the meantime you have the oil consumption. This accounts for some people having to add more oil than others. Short trips frequently will end up using more oil than the guy who travels 50+ miles every time it's driven. When engines are in marine use, and have forged pistons, they tell you that after so many hours and X amount of RPM you will use a quart or more oil. In the owner's manual it states this, and it's normal.
I’m going tomorrow to look at a 2005 8.1 with Allison . Truck has 140k miles . I’m hoping it will be as good as I see in these comments . I’m paying a premium for it , but it doesn’t have a scratch on it .
Thanks for the great info. I have a 2001 8.1 HD Sierra. I tried switching over to full synthetic oil about 15 years ago and got a severe case of lifter tick. Very loud. I thought I had a bent rod or something. I switched back to regular oil and the tick went away. I never had that issue again until I recently did an oil change and used some oil that I had bought in 2020. That real loud ticking came back, but only under a load, or when I really give it some gas like getting on the highway. You can barely hear the tick at idle, even when revving up in park. I put in a full bottle of Marvel Mystery Oil and the ticking quieted a little but its still loud. I'll be changing the oil again. Any recommendations? Im thinking of going to a fully NON-synthetic blend. ??
As posted below, run heavier oil. I only use 20-50 in ALL my vehicles. None consume a drop between oil changes. I also run 20-50 in all my small motors, like generators, etc. Saving a half gallon of gas is not worth the problems associated with light oils lack of lubrication.
The engine burns it away, so it doesn't technically go anywhere. There really isn't any easy or simple fix for it, or at least one that I would recommend trying to chase down as it will get expensive and the oil consumption issues don't really pose any issues to the 8.1.
block off the tube on the bottom of the intake (which obviously requires removal) and put a conventional pcv valve in somewhere like the oil filler cap or get a bung welded in on the back the have it run into a new hole in around the throttle body. A catch can incorporated in here is also probably a good idea.
I feel like saying the 8100 was based on the 7.4 is misleading. The 8.1 has a 10.2 deck height where rhe 7.4 was a 9.8 The 8.1 is more like the 427 tall deck than the 454
Hello, i have a 2000 3500 slt /vortec,117,000 miles /dualy/4x4 and a 2002 2500 hd /vortec 8100/147,000 miles/4x4. Trying to make a decision about what to keep and what to sale. Any suggestions. Thank you so much.
@@8020Media Well, 2002 has Allison Transmission... Im selling the Dually 2000 if you know anyone. Located Northern Virginia. Any place you recumbent for service this engines?
Good job on the information I appreciate it I had questions you answered for me on your video I do have an exhaust leak and I am getting those codes I'll see if the gasket helps me out
In some configurations, these engines can run lean, enough to grenade the pistons. I have an '03 8.2L in my big ass RV and use a scan gauge to keep an eye on What the computer is doing by monitoring the LF1 and LF2 compensation numbers. anything in the double digits is real bad. I put in a new air filter and cleaned the MAS and it brought things to low single digits...
Hi Jake, Thanks for this video. I am a owner of a 2500HD sierra 8.1 since a year ish. I got it with a truck camper combo 88 000 miles and it has now 106 500 ! I traveled all over the west part of the country and really happy with the reliability of this old mastodont. My only issue is the EGR valve, I got a light on the dash. I changed it many times and added a fancy gasket but still have the light and code. What do you think its wrong with it ? I've heard it could be good to put a plate between the gasket and the pipe. Do you think it's wise?
Hey Drum - not to ask a dumb question here but have you tried resetting the code? If it were the EGR valve itself I would think you'd be experiencing some sort of symptoms from it. Could be a bad O2 sensor too that is causing the code. What code specifically are you getting?
@@8020Media hi! I have reset it many times, but it keeps coming back randomly. Sometimes when I turn the engine on its off but will appear at some time. The code is p0404.
Drum - Interesting.. There aren't any other codes? P0404 is issues with the EGR but if you've replaced it multiple times than it shouldn't be an issue.
@@8020Media i scanned yesterday and it's still this code... Have you ever heard about putting a plate between the valve and the rest of the hoose to block it?
Yepp, that's a common thing but you might still end up with a CEL depending on how you go about it. Check out this post here - should give you an idea of how to do it: www.dieselplace.com/threads/8-1l-egr-delete.383356/#post-3972767
Very useful video ! What kind of oil would you use in that Beast ? I just bought one and the previous owner told me to use t6 Rotella , what do you think? Thanks again
I'd worry more about the weight and viscosity of the oil vs the brand honestly. A lot of people like 15w-40 in warmer months and 10w-30 in colder but that's just a subset of people. A lot will stick with the recommended 5w-30.
I have an 8.1 that will skip in any season except summer. No engine light. Replaced coils wires plugs cam sensor knock sensor, cleaned ground wires on block and frame under drivers side cab. It’s symptom is in cooler weather it severely skips when accelerating the like flipping a switch it kicks in and takes off like a rocket! When it’s doing this it stinks like hell,,, Any advise?
Zip - This is pretty common on old diesels. But other things to look into are: fuel injectors, coolant temp sensor, intake air temp sensor, and vacuum leak.
Might fires right up and then dies after a few minutes. Then its kind of a pain to get it started again sometimes. Runs fine after that. 147k. 2001. Where do i start? Crank postion sensor? Plugs?
T - Sounds like it could be an alternator issue. But throwing us off running fine after starting.. We have a video on engine stalling the could be helpful: ruclips.net/video/7bqAIbYRdnc/видео.html
I just dropped a 8.1 in my 84c10 its sweet set up so far. But when it hits 194° it hase a squeak luke a belt but its not one. Anyone have any idea? I have videos up on my RUclips page. Any info is appreciated
@8020Media the only code it has is the TPS. Code went away after the new sensor installed. I drove it for about 10 Miles with the squeak and it never missed a beat
@@8020Media I bought a suburban 2001 2500 hd over 600k Routine maintenance wit through three hydro boosters 8 tune same trans pulls my roofing trailer13k full still roiling. a lil lose but i got my moneys worth pad 55k in 2001 for it
My super low mile 8.1 smells like antifreeze from the exhaust on startup. I assume it's a head gasket. Is this a correct diagnosis and is anyone familiar with this issue?
Some of it is just natural and normal but the intake manifold is known to shift a bit which can make it worse. If you have a lot of burn then replacing the gasket and the bolts and torquing them properly can help.
have you seen a nagging problem with the knock sensor P0332 code on 8.1s? I keep getting this code and my friend tells me its a larger problem to do with the engine running lean.
Mostly because the internals can only handle a little more than 500whp before they need to be upgraded. chevytrucks.org/best-8-1-vortec-upgrades-and-mods/
I hope someone can help me i need figure out how to find a high output alternator for my 2008 Class A Motorhome 8.1 Vortec with 5,163 miles (not typo) dealers dont help me because its a motorhome.
Look at the part numbers on the unit. Use a cross reference chart to find what you need. Or have an electrical rebuilder test and verify the internals. Good luck.!
Inside mechanics joke..all engines Will use some oil..not unusual for it to be 1 qt. Down by oil change time..won't foul plugs. Pcv system also injects oil..why catch cans are so popular. I just got back from a 2300 mile trip in my 8.1 motorhome..used half qt. 36 k miles on 2004 model. If you get lifter tick YOU BETTER CK TH 710 stick!
My 8100 Silverado has a lumber rack and is absolutely chalk full of tools and materials with the trailer hitch. Cause you know, gotta tow the ditch witch around. If your truck ain’t full of shit, and you only use it to get groceries or you have an office job, you do not need a truck.
Guy I use to work with his would only burn a quart between oil changes which worked out cause he would just change the oil cause it was time to change anyway but he had all kinds of problems with the Allison transmission think he had to replace the transmission twice so he finally just sold the truck
I have two of these engines. One of them is now an 8.8. Once you replace the low tension piston rings thereby preventing oil consumption it is a wonderful engine.
T - Nice! Sounds like a good one.
I heard or read somewhere, that forged pistons are used in these 8.1L. The expansion rate is rather slow during the heating up to normal temperature and this causes excess blowby. It would explain why some people need to add a quart every 2000 miles and others longer before adding oil. The ones adding oil frequently probably drive relatively short distances. The pistons may not have expanded during most trips eating up oil. 🤔 🙄 🤷🏼♂️ The low tension rings? Are you talking about too big of a ring gap from the factory? The oil control rings or both control and compression rings? Maybe the steel used in the rings you're talking about is flimsy. They might purposely leave a big ring gap for the expansion and that would cause the oil issue. It just takes longer for forged metal to adjust to temperature expansion, I suppose.
4.3- 8.1 vortec best motors Chevy ever made..
Rmc - Although we think they are great engines, you think they are better than the Duramax's?
@@8020Media 'better' is subjective, it depends on how you are comparing them
Adam - It is subjective, and it's an opinion. We were hoping we would hear what RMC thought that to create a discussion.
Personally I like the duramax just a little better because of the fuel mileage but I do like my 8.1 they’re both great engines
We are big fans of the Duramax engine family. This is not to say we don't like the Vortec's, just prefer a duramax.
02 GMC 2500HD w/8.1 vortex and allison transmission - 4.10 gears. Bought it new and now has 325k miles on it. I love this truck! Used 2 quarts of oil aright off the lot...dealer said its normal until I pressed the issue. Turned out there was a bulletin on the intake manifold gasket causing oil consumption. After that, 1 quart every 3k miles. Crank position sensor replaced at 50k and 275k. Besides that, all I've had to do is regular maintenance, 2 fuel pumps, and a water pump. I suspect I've got a couple broken exhaust manifold bolts and the AC (totally original-never charged) is acting up. Blows 37 degrees F at the start and then cuts off after 15 mins of driving. I might add that half the total miles driven are towing miles!
M - Thanks for taking the time to share your experience!
Thanks for the info Jake. I own a 2002 Silverado 2500hd 8.1 backed to an Allison 1000, one of the best combos, 274,569 miles, running strong to. I've owned it since 2003 and knock on wood I have only have the issue with the Crank Position Sensor a couple of times and a little oil consumption. This weekend I am rebuilding the original front suspension with all new parts. Thanks again.
Todd - Thanks for the feedback! Also, thanks for sharing your experience. It sounds like you've got a good one.
Would you recommend buying one used with over 200k?
@@wesleybryant7334 Thats a tough choice. I would ask for maintenance records and look under the truck for leaks and rust. If the truck was maintained and taken care of it should be a good buy for the right price.
@@Toddderose they’re asking 15k seems to be well taken care or only thing is I can’t physically look at it because it’s online and too far to travel and check it out. But there does seem it could have a little corrosion underneath.
Great advice Todd! Thanks for assisting.
I own 3 GM vehicles from this generation: A 2005 Suburban 2500 (8.1), a 2002 Silverado 1500, and - the crown jewel - a 2004 Hummer H2 Luxury package. I bought the Suburban with 110k miles (it currently has 210k), the Silverado with 137k (it currently has 179k), and the Hummer with 53k (it currently has 79k). I daily drive all three, and have done many long-distance road trips and family outings in both the Suburban and the Hummer. I occasionally tow with all three (nothing very heavy), and have done a fair amount of light off-roading with the Suburban and the Hummer. These three vehicles have proven to be the toughest, and most reliable vehicles I have ever owned by FAR, in my total 35-ish years of vehicle ownership. In the case of the Suburban, also the most versatile and useful. GM really knocked it out of the park in the early 2000's.
P - We couldn’t agree more. Unfortunately, they don’t make them like they used to..
@@Pharto_Stinkusthey don't make them like that anymore...
I wish it wasn't so.
I have a 2001 4x4 2500 suburban with this motor. Love it.
Like - Thanks for sharing your experience!
The oil consumption issue is courtesy of the general's engineering. They put the crankcase ventilation valve in the bottom of the intake manifold where it literally ducks oil out of the lifter valley. Lawrence Tollman addresses this issue on his channel.
G - Thanks for sharing this insight!
I've had an 8.1 for just over 10 years now and wouldn't trade it for anything made today. It's in a k2500 Suburban with a 4L80E, a full floater 14 bolt rear end and 4:10 gears. It has 340,000 miles on it and it goes through a quart of oil between changes at 3-4K miles. I put E3 plugs in it with a set of 8MM plug wires from JBA headers and haven't had a plug go bad in over 25K miles.
B - Thanks for taking the time to share your experience!
Tbh the best gas engine GM has ever used in a heady duty application… don’t forget the exhaust manifold bolts like to break and annoy you. But tbh, that’s a common problem on almost every truck in the early to mid 2000s.
Yepp, exhaust manifold bolts are common on all these old big gassers - thanks for the note.
Never had problems with the exhaust manifolds studs breaking but I have had issues with my 6.0ls exhaust manifolds bolts breaking
Yeah but it is so crazy prevalent it probably should have been included. I am looking at at least one snapped off manifold bolt now actually on our 2001.
Ohwell - This is why we have the comment section. To cover things that were missed.
wouldnt ARP bolts solve the issue? @@8020Media
I have a 2003 Sierra 2500HD 8.1 gasoline that had starting issues. It would never start on first crank, would backfire while cranking but would fire up around the third crank attempt. I replaced the crankshaft sensor, camshaft sensor with no improvements. After a year of dealing with it I came across a post on a blog where they were having the same issues. He said he swapped out the timing cover and camshaft sensor with the updated 2004 version and it fixed the problem. I decided to give it a try, also got new timing chain and sprocket while I was at it and sure enough it fixed it and haven’t had an issue since.
T - Thanks for taking the time to share your experience! This will certainly help future viewers.
I’m at 220k miles on original spark plugs (all original everything) 01 8.1 4x4. Planning on replacing this weekend
MP - Thanks for sharing your experience! Sounds like you've got a good one.
Wow. They usually foul by 40 to 60 k
Great video. I found a low mile 8.1 silverado in arizona couple years ago. Regular maintenance and it runs awesome. Love mine. Put in a true dual 3in exhaust with xpipe, no muffler, stock cats. Sounds better than my jeep that has a 6.0 LS. Great trucks!!! Ive only had little/easy repairs - ac leak, hydro booster, blend door actuator and the usual suspension components wearing out. I am very anal on maintenance but i enjoy it as these trucks are easy to work on and find parts for.
J - Thanks for taking the time to share your experience! Sounds like you've got a good one. That's the way people should be with maintenance!
We had a 2001 Silverado 3500 8.1 with 4.11 gears for 10 years. Got 8.5 MPG towing our 5th wheel. Now driving a 2022 F350 dually 7.3 Godzilla with 4:30 gears. Gets 7.5 MPG towing the same 5th wheel. However, it will maintain speed up the long hills, unlike the lower HP and less tranny gearing of the 8.1
Hy - Thanks for sharing this insight and your experience!
Experiencing the same had an 8.1 with 4:10's for 20 years got 300,000 miles out of it. Got a 22 7.3 with 4:30's also and I swear the gas mileage is worse than the 8.1. You're right about the horsepower difference its almost 100hp more and you can feel it but dang I was hoping the 10speed would help more with mpg's tho.
R - Thanks for sharing your experience!
The only 2 issues I had with my 8.1 were the Mass air flow sensor and the Crankshaft sensor . Beyond that It was a powerhouse I wish I still had .
R - Glad to hear! Thanks for sharing your experience.
We have a 2001 Suburban 8.1 Vortec.... still at 187,000 Miles. We will NEVER get rid of it. We don't drive it as much, we all know they have a huge fuel appetite...😂 We love it.
R - We love our Suburban too. Thanks for sharing your experience!
You obviously haven't worked in on 8.1 engines. The claims of spark plug failure and lifter tick being "oil consumption" issues is something as a GM master tech I have never heard. The actual issue with lifter tick is directly caused by lack of oil changes and poor quality oil.
The spark plugs were originally gapped at .060 and there's a GM service bulletin that updates the plugs to a iridium tip plug with .040 gap. This update solves a starting issue in some spplications in cold weather and is said to improve fuel mileage. I have never heard of plugs failing due to oil consumption and "contamination". Maybe on a poorly maintained high mileage engine but certainly not a normal condition. The plugs generally last 100k without issues.
The 8.1 has a cast aluminum intake manifold and is not know for intake gasket failures. This is a common failure in the small block 4.8 -6.2 liter V8s due to the incredibly cheap plastic intake manifolds and the extremely light torque spec for intake bolts. This is not an issue on the cast aluminum intake.
The oil consumption issue is directly related to piston skirt design and is common to all late model GM engines.
The 8.1 engine has very few issues and GM engineers designed the engine for a 200,000 mile service life. The critical issue is use only high quality synthetic oil and change at 3,000 mile intervals.
Lifter tick due to poor oil quality is corrected by adding Riselone High mileage oil treatment. This additive will clear the lifter issues.
Thanks for the expert advice!
With a 120k mile 8100, getting a off beat knock. Oil pressure needle vibrates and just over 40psi. Runs smooth, started after sitting 2 years because afraid of the knock. Need a trick to diagnose w/o ripping out. 20w-50 will try first
S - Thanks for sharing your experience. Keep us updated.
About to buy a 04 with 112k on the dash 😅 ❤ very excited
G - Nice! Very exciting.
You should easily be able to get another 100k out of that dash. The rest of the truck will outlive the dash! LOL 😅😂😅
8.1 6.0 and 5.3 have the same air intake gasket problem and knock sensor codes. But 8.1 is a beast that is for sure
Mile - Thanks for sharing this insight! We completely agree.
What is the cause of the knock sensor issues?
@@lpanizza2276 a big one is water running underneath the intake plenum and rusting the knock sensor out
I have a 2001 suburban 2500 4x4 8.1l and it drives very smooth
C - Nice! Sounds like you take great care of it. How many miles do you have on it?
I have not heard of a lot of these - but the 8.1 in my Avalanche had a camshaft lobe failure. Spalling on the tip of the lobe until it lost enough height to cause a lifter click at higher rpm. However, after replacement at 107,000 it has been fine and is now at 203,000.
Steven - Thanks for sharing your experience and insight!
I just replaced my spark plugs for the first time. Kind of embarrasing for 301000 miles. They looked perfect. Didn't even need changing. I have replaced the radiator, water pump, hydro boost for brakes and the crank position sensor and all the obviuos brake, bearings,and front suspension. Still same transmission with no service besides flushes. The most reliable engine I have had in 40plus years as a mechanic. And still fun to blow away average vehicles off the line with 455 lbs of torque
Erik - Thanks for sharing your experience! We love hearing it and it will help future viewers.
Only problem I ever had with mine was when I went through a phase of using 93 octane fuel. The plugs DO NOT like that. Keep it to 87 octane, change your oil regularly and it's a beautiful platform.
Adam - Thanks for sharing your experience!
I love mine i have a 8.1 i bought in San Diego for 6000 from original owner this will be a lifetime ride and it is just amazing bought it with 140000 and now has 143000 best investment ive made in years
Mag - Keep us updated on this!
How is it treating you ? Looking at buying one right now in NorCal for 5000 with 300,000 on it
Exhaust manifolds tend to leak and warp pretty bad by the downpipe
Chev - Thanks for the added insight! Do you have a 8.1?
Ahh judging by the likes im not the only one.
Almost 300000 miles on my 8.1 great motor
J - Nice! Sounds like you take great care of it.
Great tutorial! Thanks!
Roger - Thanks for the feedback. Hope it was helpful!
I had nitrous on one of my 8.1 and turbocharged another. Great engine had a lot fun with them.
Greasy - Nice! They sound like some sweet trucks.
The only problems I have had since 2001 was oil consumption but switched to royal purple 10w 30 synthetic , intake manifold bolts come loose do to vibration and replace crankshaft position sensor and a mass air flow sensor other than that it’s a solid truck zero rust starts every-time just keep the maintenance no problems also upgraded brake lines and brake systems to stainless steel and new stainless steel fuel lines and a fuel pump but she never says no or ever stranded me
John - Thanks for sharing your experience. This will certainly help future viewers!
I'm in the market fir the 8.1 now fir my 37 Pontiac 4x4 crawler. Great info! I'm a Duramax guy now, but 8.1 is a simpler option for this build.
A - Thanks for sharing! Keep us posted.
@@8020Media try a used 6500 from uhaul. They are all 8.1.
I have an 01 2500HD 8.1 I knew he was gonna bring up the crank sensor lol.
Chris - Yes. Thanks for sharing your experience.
I ran my stock plugs for 130000 miles without issues
Holly - Unfortunately not all engines, or engine components, are created the same. But that's great to hear! Thanks for sharing your experience.
Replaced my 8.1 plugs at 19 years and 157,000 miles.
Rough start and idle stopped.
my crank position sensor went out as i was pulling into my driveway but it was a knuckle buster to replace
Erik - Thanks for sharing your experience!
I have a 2005 crew cab with 8.1 and Allison that I bought new. Only problem I ever had was the gauge cluster and driver door latch. Did the transfer case pump rub fix early.
H - Thanks for taking the time to share your experience.
Thanks I'm looking at buying a 2004 right now
Ben - Just have to make sure it was maintained well in the past! This things can be work horses if taken care of.
Good ol 496. Last of the big blocks
Cod - So true..
Thanks I loved my 6.0
H - Thanks for sharing!
What’s the best exhaust sound for these 8.1?
i - This is subjective, so it's hard for us to really give an answer here.
@@8020Media thanks for responding anyways, I’ve decided to get rid of my cats, and straight pipe to a FM delta series 50. If you’re interested in hearing it I’ll post a video.
i - Wouldn't hurt!
I daily my Avalanche 8.1L. BG EPR and 5k oil changes. Shes a beast
S - Nice! Sounds like you've got a good one. Thanks for sharing your experience!
It was available until 2009 last year gm produced medium duty trucks
GM Fan - Thanks for sharing this info!
@8020Media no worries love gm trucks
The 8.1 went to 2009 in gm trucks? Never seen any past 06 and all info I've seen online 06 was the final year.
@benzoil0453 in trucks 2500 3500 its in until beginning of 2007. 4500 5500 6500 7500 8500 it was available in koadiak until 2009 last year gm produced medium duty trucks
@@gmfan6029 Oh I gotcha, good to know 👍.
Great video! Don’t forget exhaust manifold leaks due to cracks, broken bolts and worn gaskets.
C - Thanks for the feedback! Very true!
Great video, just bought a one owner, 2002, it has 160k, what about Rizlone for lifter tick?
Jeremy - Thanks for the feedback. Rislone can be beneficial, so long as you know it's not a guaranteed fix.
One of the main reasons for the oil consumption issue is the clearances on the internals
Joe - Thanks for sharing this insight.
@@8020Mediayou're welcome
A lot of it has to do with big blocks running forged pistons and it takes a while for them to expand. In the meantime you have the oil consumption. This accounts for some people having to add more oil than others. Short trips frequently will end up using more oil than the guy who travels 50+ miles every time it's driven. When engines are in marine use, and have forged pistons, they tell you that after so many hours and X amount of RPM you will use a quart or more oil. In the owner's manual it states this, and it's normal.
W - Thanks for sharing this insight!
I’m going tomorrow to look at a 2005 8.1 with Allison . Truck has 140k miles . I’m hoping it will be as good as I see in these comments . I’m paying a premium for it , but it doesn’t have a scratch on it .
Pb - It all depends on how well it was previously maintained. They can be work horses.
Update?
Did you get it?
@@donc6781 nope , got there and the guy lies to me about oil leaks , and when I started it it was smoking blue . I just walked away
My 8.1 with 161,000 has never had any problems except a bad crank position sensor and now the one you can’t forget……oil cooler lines.
Todd - Nice! Thanks for sharing your experience!
Thanks for the great info. I have a 2001 8.1 HD Sierra. I tried switching over to full synthetic oil about 15 years ago and got a severe case of lifter tick. Very loud. I thought I had a bent rod or something. I switched back to regular oil and the tick went away.
I never had that issue again until I recently did an oil change and used some oil that I had bought in 2020. That real loud ticking came back, but only under a load, or when I really give it some gas like getting on the highway. You can barely hear the tick at idle, even when revving up in park. I put in a full bottle of Marvel Mystery Oil and the ticking quieted a little but its still loud.
I'll be changing the oil again. Any recommendations? Im thinking of going to a fully NON-synthetic blend. ??
As posted below, run heavier oil. I only use 20-50 in ALL my vehicles. None consume a drop between oil changes. I also run 20-50 in all my small motors, like generators, etc. Saving a half gallon of gas is not worth the problems associated with light oils lack of lubrication.
Foley - Thanks for adding this insight!
Add motorcote
I run the Rotella t6 oil in everything. Lawn mowers, atvs, my 6.0 chevy, etc lol
Running heavier oil isnt recommended for the 8.1
@@Zkgod24in the marine version it’s recommended to run 20-40
Where does the oil go in terms of consumption? Is there a fix for this?
The engine burns it away, so it doesn't technically go anywhere. There really isn't any easy or simple fix for it, or at least one that I would recommend trying to chase down as it will get expensive and the oil consumption issues don't really pose any issues to the 8.1.
Run sythetic oil that will help
Agreed!
I run royal purple 10-30 and when it starts eating up the oil I top it of with Lucas oil stabilizer
block off the tube on the bottom of the intake (which obviously requires removal) and put a conventional pcv valve in somewhere like the oil filler cap or get a bung welded in on the back the have it run into a new hole in around the throttle body. A catch can incorporated in here is also probably a good idea.
I feel like saying the 8100 was based on the 7.4 is misleading. The 8.1 has a 10.2 deck height where rhe 7.4 was a 9.8 The 8.1 is more like the 427 tall deck than the 454
Eric - Thanks for the insight.
I have a 2003 8.1 manufactured late 2003 for the 2004 model year,how do I know if I have the crankshaft sensor fix from the factory?
R - The best way is to visually inspect it if possible.
Hello, i have a 2000 3500 slt /vortec,117,000 miles /dualy/4x4 and a 2002 2500 hd /vortec 8100/147,000 miles/4x4. Trying to make a decision about what to keep and what to sale. Any suggestions. Thank you so much.
C - We like them all. That's a tough decision.
@@8020Media Well, 2002 has Allison Transmission... Im selling the Dually 2000 if you know anyone. Located Northern Virginia. Any place you recumbent for service this engines?
C - Should sell easily.
Manifold leaks need to be addressed more urgently than you imply , it can cause very serious damage
John - Thanks for the insight here. This will certainly help future viewers!
Good job on the information I appreciate it I had questions you answered for me on your video I do have an exhaust leak and I am getting those codes I'll see if the gasket helps me out
T - Glad to hear it was helpful! Thanks for the feedback.
Donde puedo conseguir partes originales o reemplazo para 8.1 necesito inyectores sensores del cigüeñal y más
J - Pueden ser difíciles de encontrar. Ebay puede ser tu mejor ruta.
In some configurations, these engines can run lean, enough to grenade the pistons. I have an '03 8.2L in my big ass RV and use a scan gauge to keep an eye on What the computer is doing by monitoring the LF1 and LF2 compensation numbers. anything in the double digits is real bad. I put in a new air filter and cleaned the MAS and it brought things to low single digits...
M - Well said. Thanks for taking the time to share your experience!
Hi Jake, Thanks for this video. I am a owner of a 2500HD sierra 8.1 since a year ish. I got it with a truck camper combo 88 000 miles and it has now 106 500 ! I traveled all over the west part of the country and really happy with the reliability of this old mastodont. My only issue is the EGR valve, I got a light on the dash. I changed it many times and added a fancy gasket but still have the light and code. What do you think its wrong with it ? I've heard it could be good to put a plate between the gasket and the pipe. Do you think it's wise?
Hey Drum - not to ask a dumb question here but have you tried resetting the code? If it were the EGR valve itself I would think you'd be experiencing some sort of symptoms from it. Could be a bad O2 sensor too that is causing the code. What code specifically are you getting?
@@8020Media hi! I have reset it many times, but it keeps coming back randomly. Sometimes when I turn the engine on its off but will appear at some time. The code is p0404.
Drum - Interesting.. There aren't any other codes? P0404 is issues with the EGR but if you've replaced it multiple times than it shouldn't be an issue.
@@8020Media i scanned yesterday and it's still this code... Have you ever heard about putting a plate between the valve and the rest of the hoose to block it?
Yepp, that's a common thing but you might still end up with a CEL depending on how you go about it. Check out this post here - should give you an idea of how to do it: www.dieselplace.com/threads/8-1l-egr-delete.383356/#post-3972767
Looking into buying a 2001 8.1 GMC Sierra. What should I look for before buying?
K - The things we've mentioned in the video. Make sure to get maintenance records. These things can be great if they've been maintained properly.
Very useful video ! What kind of oil would you use in that Beast ? I just bought one and the previous owner told me to use t6 Rotella , what do you think? Thanks again
I'd worry more about the weight and viscosity of the oil vs the brand honestly. A lot of people like 15w-40 in warmer months and 10w-30 in colder but that's just a subset of people. A lot will stick with the recommended 5w-30.
My dad has a 02 silverado with the 8.1 with only 147k miles he thought it was a regular 6.0
Henry - Thanks for sharing his experience.
I have an 8.1 that will skip in any season except summer. No engine light. Replaced coils wires plugs cam sensor knock sensor, cleaned ground wires on block and frame under drivers side cab. It’s symptom is in cooler weather it severely skips when accelerating the like flipping a switch it kicks in and takes off like a rocket! When it’s doing this it stinks like hell,,, Any advise?
Zip - This is pretty common on old diesels. But other things to look into are: fuel injectors, coolant temp sensor, intake air temp sensor, and vacuum leak.
Do a live stream and look at knock sensors....
Might fires right up and then dies after a few minutes. Then its kind of a pain to get it started again sometimes. Runs fine after that. 147k. 2001. Where do i start? Crank postion sensor? Plugs?
T - Sounds like it could be an alternator issue. But throwing us off running fine after starting.. We have a video on engine stalling the could be helpful: ruclips.net/video/7bqAIbYRdnc/видео.html
I just dropped a 8.1 in my 84c10 its sweet set up so far. But when it hits 194° it hase a squeak luke a belt but its not one. Anyone have any idea? I have videos up on my RUclips page. Any info is appreciated
K - Any engine codes?
@8020Media the only code it has is the TPS. Code went away after the new sensor installed. I drove it for about 10 Miles with the squeak and it never missed a beat
K - Nice! Great to hear you got it resolved!
Would a catch-can system help at all with the carbon issues?
Blackthorn - Yes, they can certainly help!
8.1one of best Eng ever
Robert - We completely agree!
@@8020Media I bought a suburban 2001 2500 hd over 600k Routine maintenance wit through three hydro boosters 8 tune same trans pulls my roofing trailer13k full still roiling. a lil lose but i got my moneys worth pad 55k in 2001 for it
My super low mile 8.1 smells like antifreeze from the exhaust on startup. I assume it's a head gasket. Is this a correct diagnosis and is anyone familiar with this issue?
J - Based off of what you described, it could be the head gasket. Are you having any drivability issues?
What’s the cause of the excessive oil consumption?
Some of it is just natural and normal but the intake manifold is known to shift a bit which can make it worse. If you have a lot of burn then replacing the gasket and the bolts and torquing them properly can help.
The unconventional pcv system that sucks in oil from the lifter valley...mostly in periods of deceleration with high vacuum.
@@kbitbit soooo what I hear you saying is run a bigger cam to get the dope lope and fix the pesky high vacuum oil draw at the same time?… 😆
2005 suburban 8.1. Lifter noise stoppped by full synthetic oil.
Had rough start power loss, plugs replaced.stopped .
H - Thanks for taking the time to share your experience. It will certainly help future viewers.
have you seen a nagging problem with the knock sensor P0332 code on 8.1s? I keep getting this code and my friend tells me its a larger problem to do with the engine running lean.
J - We wouldn't say it's a common problem that we have seen with 8.1's. This could be a silly question but have you replaced the knock sensor?
@@8020Media I havent yet. I plan to. I have just heard from some RV forums that the knock sensor is a sign that there is a larger issue at play.
What causes the oil consumption?
P - Could be a lot of things. Did you listen to our part in the video?
These things are awesome with a carburetor swap
Texas - Completely agree.
best engines ever bullet proof!
Cory - We agree! They are solid.
Never changed the plugs in ten years of ownership
Mason - This is quite surprising. How many miles are you at?
Could you swap a 8.1 into a 2007 Silverado?
Soggy - You technically can, it would just be difficult and a tight fit.
They came from the factory in the Classic Silverado but not the New body silverado in ‘07 .
My 8.1 is terrible on gas mileage. Would a 6.0 get me better gas mileage?????
H - 6.0 would be better, yes.
Axel ratio is a key factor here, what ring and pinion does your truck have? 4.10 etc. just match the gears to your load towing needs.
Why does a lot of ppl think these will break like glass when you throw power at them?
Mostly because the internals can only handle a little more than 500whp before they need to be upgraded.
chevytrucks.org/best-8-1-vortec-upgrades-and-mods/
I hope someone can help me i need figure out how to find a high output alternator for my 2008 Class A Motorhome 8.1 Vortec with 5,163 miles (not typo) dealers dont help me because its a motorhome.
Michael - Those can certainly be hard to find.. We can try to look around.
Look at the part numbers on the unit.
Use a cross reference chart to find what you need.
Or have an electrical rebuilder test and verify the internals.
Good luck.!
Hummm? Is that what the yellow 710 stick is for..ive seen that on all th cars n trucks ive owned
Rob - Not quite sure what you mean here.
@@8020Media lol..read it upside down
Inside mechanics joke..all engines Will use some oil..not unusual for it to be 1 qt. Down by oil change time..won't foul plugs. Pcv system also injects oil..why catch cans are so popular. I just got back from a 2300 mile trip in my 8.1 motorhome..used half qt. 36 k miles on 2004 model. If you get lifter tick YOU BETTER CK TH 710 stick!
Hey other than excessive oil use it's a great engine
C - Well said!
My 8.1 has ticked since the day I bought it.
C - More of just an annoyance. How long have you had it?
Try synthetic oil.
My 8.1 lifer tick went away with amsoil.
My 8100 Silverado has a lumber rack and is absolutely chalk full of tools and materials with the trailer hitch. Cause you know, gotta tow the ditch witch around. If your truck ain’t full of shit, and you only use it to get groceries or you have an office job, you do not need a truck.
Jordan - Well said!
Can a 2500hd 8.1 be faster than a Bugatti?
K - Uh, depends how much you're trying to spend lol
C.H.E.V.Y
Can Hear Every Valve Yelling
J - lol.
I got 7.4,going in camaro!
H - nice.
Guy I use to work with his would only burn a quart between oil changes which worked out cause he would just change the oil cause it was time to change anyway but he had all kinds of problems with the Allison transmission think he had to replace the transmission twice so he finally just sold the truck
Ah that's a bummer - the Allison is usually the more desirable of the transmission options.
Just run heavier oil on these… problem solved. Bbc like 10-40 or 20-50
Absolutely agree!
Workhorse doesn't recommend using 10w40 oil in the 8.1 engine.
Gas ?
Joe - Are you asking if it's a gas engine or what gas to use?
Mine just quit on me:(
Bingo - Sorry to hear this! Do you know what happened?
Own one fun to drive but hard on gas lol
D - Thanks for sharing and well said lol
Tow a big trailer and it consumes a lot of oil. Must use high octane fuel.
E - Well said.
No Honda love here?
S - We have some Honda content? We aren't going to talk about Honda on a 8.1 Vortec video..
There are no 8.1 problems
Well Evan - Unfortunately that isn’t true
Yes there are but they are only minor problems . There is No “Perfect Machine” manufactured by Anyone Anywhere .
R - Agreed. Well said.