Help ! Sudden large oil consumption

[Tim B]

Hi everybody - I sure hope someone can help me here.
I have a 2002 2500HD with the Duramax and Allison combo. I bought it new and recently sold it to my son. It now has about 105,000 miles on it and has never had any problems.

We just discovered that it has sucked down 3 1/2 qts oil (Mobil 1300S) in only a couple thousand miles. That's a huge change as it has NEVER used much, if any, before. There are no leaks and it IS pushing blue smoke out the tailpipe.

Can anyone provide a guess as to what's going on here ? The only thing out of the ordinary is that we are WAY behind on changing the fuel filter. Could that somehow lead to the problem (some sort of weird combustion chamber vacuum pulling oil past the rings because of decreased fuel flow) ?

Could there be an oil leak at the turbo that's getting sucked in ?

Can oil leak past the injectors under the valve covers ?

The air filter is OK according to the gauge but I'm going to pull it tomorrow to inspect it and most likely change it out anyway.

Stuck rings ?

Any other guesses ?

What is the most likely reason ?

We do the oil changes so I know it was not underfilled at the last change.

Also, I live in Florida so this is not a cold weather-related problem.

There are no 'check engine' lights coming on.

Any assistance will be much appreciated !

Thanks again,

Tim B.

[Duramaster]

Is the truck a STOCK vehicle? If not, what modifications have you done?

[DickWells]

Don't really have any good ideas about the cause, but an observation or two about what I'd do if it happened to me with the same truck.
I had my injecters changed in Aug. 07, no charge. The injecter cups were replaced with the latest up-graded ones at the same time.
My wild guess would be that you have one or more cups letting oil by the seal, into the combustion chamber.
A dealer is obligated to fix this problem, (if that, or something related is the problem) under the 200K-7year special warantee policy. Diagnostics will tell them (GM) where your problem is, so you should know what has to be worked on, going in. BTW, it didn't cost me a cent for the diagnostics, or the new cups, or the scoping of the chambers and piston crown, or the checking of the valve lash, either. They knew that I had 3 bad injecters without taking anything appart.
If a dealer gives you a hard time, go somewhere else. Sterling GMC, up in Longview, Wa. was good as gold for me.
Best of luck.
Dick Wells:)

[Tim B]

Duramaster - The truck is 100% stock.

Dickwells - I've read about the injector warranty - I guess you're saying that includes the injector cups too ?

Where can I find out what the warranty covers ? I'd like to know prior to taking it into a dealer.

Thanks guys !

Tim B.

[More Power]

An LB7 injector cup problem usually involves the cooling system (overpressure, consuming coolant, etc.).

Pulling the glow plugs would provide an indication as to what cyls might be burning oil. If it's all eight more or less uniformly, it might be the turbo, but a turbo being the cause of an excessive oil consumption problem is pretty rare... Be sure to use anti-sieze compound on the glow plug threads during installation.

Is it possible that the oil wasn't brought to the correct level at the last oil change? Did you measure it today while the truck was sitting level? Was the engine at operating temperature (or cold and not started recently) when checked?

Jim

[Mark Rinker]

Within the last month, both my '06 and '04 used uncharacteristic amounts of oil. Neither truck has an oil consumption history. The '06 was an alarming two quarts low when the indiator light came on. The '04 used a staggering 4 quarts in 8,000 miles.

No definate answer as to why. Both towed a fairly large and heavy boat in frigid cold, windy conditions.

Any unusual weather or towing duties? How about a filter leaking under pressure? Until you change the oil and filter and operate the truck for at least another 5K miles, I wouldn't consider it a trend line. I am watching carefully this month.

[Tim B]

More Power - I changed the oil and I am absolutely positive that I added 10 qts (to the 'full' line). When measured Friday the truck was sitting level and hadn't been run in several hours.

Mark - No weird weather here (central Florida) and the truck does not tow much at all. In fact, the last time I towed with it was prior to the last oil change. I don't believe oil is leaking past the filter because I have not observed any oil mess on the ground and I don't see any around the filter or on the chassis. Also, blue smoke coming out the exhaust so I believe oil is getting into the combustion chambers somehow.

Thanks,

Tim B.

[DickWells]

Tim B.
There, that didn't take long for the good guys to get back to you. The DP is awsome!
I wouldn't worry too much about dealer cost. If one guy gives you a bad feeling, go to someone else. I've had good experience with Chevy and GMC dealers in the following locations and in this order.
1999-Bill Buck Chevrolet in Venice, Fl.
1999-2000 to 04 at McMahon Chevy in Morrisville, Vt.
Forgot about Brown Chevy in Mesa, Az, 2002!
2006 -07 at Brown Automotive in Del Rio, Tx.
2007 Stirling GMC in Longview, Wa.
Have yet to have a BAD experience with a GM dealer. Waiting for the other shoe to drop, hoping that it never does. If it does, I'll move on down the road, even if I have to pay someone to tow me.
If it turns out to be your turbo, then (I think) they're obligated to fix that, too.
Every time I hear about these issues with a DM, I just thank God I have a 6.6 GM, not a 6.0 L Ford! I've only met one guy with 6.0 problems that got them resolved without a BIG run-around.
Again, you're getting good poop from these guys that know way more than this ole hillbilly.
Dick Wells:)

[Duramaster]

The oil consumption rule of thumb from GM is 1 quart per 100 gallons of fuel used. You might try performing your own oil consumption report. Remember to let the vehicle set for 10 to 15 minutes before checking the oil.

[Mark Rinker]

Using that rule - I'm still doing okay. Weird thing is, little to no oil consumption between oil changes prior on either truck, and then they both do it??? Both have pulled plenty of big boats cross country, but in warmer weather...what changed? Some combination of super cold air temps and load? Hmmm...

Sounds like the other problem reported here is mechanical, but a hanging injector is the much more common culprit for smokey exhaust. Don't chase the wrong issue - maybe the hanging injector is diluting the oil and its making it past the rings faster than its getting diluted?

Either way I'd change the oil and filter and watch it carefully. If it continues - have the dealer check injector balance rates first to rule out injectors, then have them do a compression test if you still suspect rings or other compression related problem.

[DieselMonk]

hmm... would be interesting if you could get an oil sample analyzed... :D

[Tim B]

Well boys and girls, looks like it's new turbo time. The truck barely runs. HUGE cloud of smoke if you punch the throttle at all (distinct blue tint and heavy oil smell). And it appears to be ingesting oil faster then I can put it in. After being driven only a short distance, it was 1/2 qt low.

I stopped at a local Chevy dealer. Luckily, their diesel whiz was working so I got to have a long talk with him. His opinion, based on the symptons is that the turbo blew a seal. Could be the exhaust side or the 'fresh air' side. But he will check everything.

I'm actually praying it's the turbo and not a brocken or stuck piston ring. The tech basically said if that's the case it's cheaper to buy a new motor then do a rebuild of the existing engine.

The truck has 104,000 miles on it. Chevy and I are going to have a heart to heart talk about the fact I'm 4000 miles out of warranty. If the odometer is off by 4% then I would still be IN !

The truck will be towed to the dealer Sunday. I'll let you know the verdict.

Tim B.

[Duramaster]

You could look under the vehicle at the turbo exhaust outlet pipe connection to see if there is any oil dripping from the joint. That would confirm the leaky turbo seal.

[Tim B]

Per the Chevy dealer, it's a blown turbo. Dumping oil down the fresh air side.

Tim B.