8.1 problem list

[George Schweikle]

Because it's a slow Sunday morning and I have been reading other posts regarding the 8.1, I googled the topic and came up with this:

https://www.youtube.com/watch?v=pXIdvgvy6lM

They list the five common problems with the 8.1:
1. Excessive oil consumption
2. Spark plug fouling
3. Lifter "Tick" noise
4. Intake manifold leaks
5. Crankshaft position sensor failure

Of course the internet should sometimes be taken with a little grain of salt and there was no mention of spark plug wire failures. That said, to date at 67,000 miles, I haven't experienced any of these issues and am very pleased with the 2005 Safari Trek we bought with 52,000 miles (although I did have to replace a harmonic balancer). Just wondering how many other happy owners are out there; just to provide a positive element to some of the problems listed here.

[ntinling]

2001 P32. 90,000 miles. Excessive oil consumption and Crankshaft Sensor failure. Oil consumption reduced by changing to 10/30 weight. Spark plug wires upgraded, so no problem there.

[OldTimer]

George,

Thanks for the research. I have the same Trek year and model as you. I purchased it new and have 28,000 miles on it now. The only engine problem has been the belt tensioner that was replaced in the first year under warranty. And I had to add the side air seals between the radiator and fan shroud because there weren't any. I carry a MAF sensor just in case and used a ScanGauge and just upgraded to a III. I drive it at least once a month for 30 miles on the highway to try to keep the fluids moving and the seals soft. I am very happy with the 8.1. And I thank all the folks that post about their problems so I can keep track of the cures.

[Alan_Hepburn]

We've got about 55K miles on our 2007 Bounder now, and the only issue we have with the engine just appeared during the last outing: pulled the oil dipstick out to check the oil level and cannot get it to go back in all the way. It has always been tricky, and I have had to "jiggle" it up and down to get it past that last turn in the feed tube - now it won't go past that turn no matter what I do.


Since it has never needed any oil between oil changes I've decided that, until I can get it looked at by my service shop, I can easily verify the level by draining it and replacing the oil with the correct amount.

[fivejacks]

oil consumption is ok 112000 miles current problem is rad. fan lost some blades and put holes in the radiator and took out the shroud new fan new rad. no problem,. cannot find a upper shroud any where in the country, and no one is making one at this time. If you have a older plastic fan check it out or replace it. Much cheaper.

[SandiaMan]

Our 8.1L with allison 2000 series powertrain has proven to be a bullet proof combo thus far, I have not seen any issues from above list occuring although we only have 45K miles on the odometer. Has more than enough grunt for our 40' rig and effectively pulls our GMC Terrain toad around the mountain west and four corner states where we do 90% of our RVing. Another plus, although I am not a mechanic, how easy to keep up with service and maintenance intervals with all the room/space around the 8.1 on our W24 chassis, an oil & filter change takes about 10 minutes to do.

[AveryF]

Our 8.1 has been basically bulletproof but does burn a quart of oil every 1500 to 2000 miles or so. Very reliable overall with only routine maintenance.

[Mark_K5LXP]

If there's one thing I can say I like about my P32 workhorse it's the 8.1 vortec. It's a runnin' machine, still has stock plugs and wires at ~65K. Just hoses, belt and oil changes so far. I run 10/30 and use about 1 quart per 1500 miles. I watch short and long term fuel trims while underway and they're rock solid. Starts easily hot or cold, and after a winter slumber. Love the way the dual exhaust sounds as it idles. Nope, they don't make 'em like this anymore and likely never will, so I'm enjoying it while it lasts.

One thing I check for is broken exhaust manifold bolts. Not a unique problem to the 8.1 but can be an involved project.

Mark B.
Albuquerque, NM

[yeloduster]

Big block GM truck engines of all vintages tended to use oil when the engine was worked hard.

GM has a spec for oil consumption for the 8.1L engine. The spec is 1 quart per 100 gallons of gasoline. Oil consumption must exceed this or GM would not investigate for warranty work.

If you get 7 MPG then 1 quart per 100 gallons would be 1 quart per 700 miles! I think that if you have a 8.1L Avalanche it may be common for the engine to use no oil. If you have a truck or motorhome, tow a car or 5th wheel and drive mountains a lot oil consumption is more likely to be a quart every 1500 miles.

One quart per 1500 miles seems to be rather normal as reported here on IRV2. People who report no oil consumption either have an exceptional 8.1L engine or they live somewhere that the engine seldom works hard.

Gasoline engines that are worked hard tend to use some oil regardless of engine brand.

[Flyer15015]

So far I've put about 25K miles on our "new to us" 2004 pace Arrow, and we are sneaking up on 50K for the rig.
I use 10w-40 Mobil 1 full synthetic and a can of "Restore" with every change at about 5K miles. Never had to add oil between changes. We mostly tow an '02 Grand caravan on a dolly or an 8K# enclosed car hauler all over the Colorado mountains. We did the Ultra RV mods as per our signature and the deep PPE Tx pan and fan switch mod really helps keep the Allison cool when climbing Monarch Pass. When I have the bike on a rail, I drive her like a hot rod.
Seven to eight MPG with the toad and I'm a happy camper.
Remember what they say, ABC = Always Buy Chevy.

Mike in Colorado

[CamJam1]

Originally Posted by ntinling

2001 P32. 90,000 miles. Excessive oil consumption and Crankshaft Sensor failure. Oil consumption reduced by changing to 10/30 weight. Spark plug wires upgraded, so no problem there.

Mine also used a quart of 5-30 every 1,500 miles, and since I changed to 10-30 I no longer need to add any oil between changes.

Only thing I've had to do to mine is change the MAF, as the long-term fuel trims were creeping upward over time. I did upgrade the plug wires to Ultra RV's, but that was just PM and not due to any problem.

[bobmar]

Our ‘03 Winnebago Adventurer has 52,000 on it. Always used Mobil1 5W30 and a NAPA Gold filter. Change oil at the end of each season at between 3-4k.
It’s always full. I know this engine enjoys oil but this girl seems different.
We’ll love this 8.1 until we don’t!!

[George Schweikle]

I'm back. Your fuel trim issue sounds familiar. Ours is now around 72,000 miles, and the fuel trims are creeping over 10. If cleaning the MAF doesn't work, I will buy a new one and also clean the Oxygen sensor wire connections. It came with the Brazel's plug wires, and I added their engine and transmission tunes with good results. Consumption of Mobil 1 10-30 is minimal.

The only other issue was a failed serpentine belt that I replaced and then read here about the harmonic balancer pulley misalignment issue that led me to replace it. Note, if you need one your parts store will likely offer a balancer from a 8.1 Pickup/Suburban but these will have two belt pulleys. Our 8.1 engines only have one pulley and this can be found by viewing the parts images that most parts stores have. My refundable rental of the installation tool was $150 and the balancer could not have been removed/replaced without this gadget.

Still lovin' our Monaco Workhorse Safari Trek

[QUOTE=CamJam1;6693321]....Only thing I've had to do to mine is change the MAF, as the long-term fuel trims were creeping upward over time..../QUOTE]