C5 burning oil?

[Ebein]

Hey Joe!

Thanks so much for lending your expertise to our Forum!

I just bought my first Vette ( 2001 Coupe, almost 22k miles ).
I bought it with 18,444 miles on it and its been going through
about 1 quart ever 1000 miles or so.

Ive read on Corvetteforum.com that the Rings may not have seated yet or could be high rpm/low load ( cruising at high rpm ).

Is this truely a common problem, and is there anything I
can check or do to ensure its not a more serious issue?

Thanks,
Bill Linton

[EbVette]

Not stealing Joe's thunder, but thought maybe some background information might help you since this is your first vette...

If I recall correctly, the changeover in the rings (which supposedly eliminated the oil burning problem) took place during 2002 production. However, lots of 2001s never experience any significant oil burning. I believe the problem was more pronounced in the manual transmission cars than the automatics. My 2002 automatic has never had any oil burning problems.

So here you are the Service Bulletin:

1999-2002: Service Bulletin: Higher Than Expected Oil Consumption
Subject: Higher Than Expected Oil Consumption (Replace Rings and Engine Valley Cover)
Source: Chevrolet Dealer Technical Service Bulletin
Number: 01-06-01-023A
Models: 1999-2001 Chevrolet Camaro, 1999-2002 Chevrolet Corvette, 1999-2001 Pontiac Firebird, with 5.7L Engine (VINs G, S -- RPOs LS1, LS6)

This bulletin is being revised to add model years for the Corvette, information on the LS6 engine and parts information. Please discard Corporate Bulletin Number 01-06-01-023 (Section 6 - Engine).

Condition
Some owners may comment on higher than expected oil consumption. When checked, the oil consumption could be in the range of 400-600 miles per quart (700-1000 km/L).

On the LS6 engine only, the technician may find oil behind the engine throttle plate and in the intake manifold.

Cause
The cause for this condition may be an interaction between the piston rings and the cylinder bore in vehicles that are operated at higher RPMs -- typically manual transmission vehicles driven in a manner where the engine is frequently or consistently operating at greater than 3200 RPM.

On the LS6 engine only, the engine has a unique aluminum valley cover that has composite oil separating baffles and PCV plumbing incorporated. In some cases, the PCV baffle may not be properly sealed to the valley cover, causing oil to enter the PCV system.

Correction
On the LS6 engine only, replace the engine valley cover if oil is found behind the throttle body or in the intake manifold before replacing the piston ring. Refer to Engine Valley Cover Replacement in the Engine Mechanical - 5.7L subsection of the Corvette Service Manual.

A new set of piston rings is currently available through GMSPO. The new rings are part of a complete piston ring kit. Install only the number 2 compression ring and the oil expander ring from the piston ring kit. All other rings in the piston ring kit should be discarded. The original number 1 compression ring and the oil ring rails should be re-used in their original positions on the piston. All pistons should be used in the same cylinder bore.

Important
Do not dress or hone the cylinder bore. Nothing should be done to change the bore finish for this condition. Changing the bore finish may aggravate the condition.

Refer to the Unit Repair Manual for appropriate ring removal and replacement procedure.

The number 1 compression ring and the upper and lower oil expander rails are re-used because they are already broken in for the bore that they are in. The new number 2 compression ring is made with a very sharp edge that will break in quickly.

Changing only the piston rings noted, with no change in driving style, should change oil consumption to an acceptable level. Changes in driving style that reduce the amount of time spent at higher RPMs will also positively affect oil consumption.

In addition to the standard size piston ring kit listed below, a 0.25 mm oversized piston ring kit is available. The oversized piston ring kit should only be used in those rare instances where the cylinder bore size has been machined larger to accommodate the 0.25 mm oversized piston rings.

There were several articles published the last few months about and in the past regarding the amount of oil being used (burned up) by the LS-1. Excessive knocking, piston slap and oil consumption. All seem to be related. These are the steps that are recommended.

One of the first things you need to clean the carbon from your engine. The Chevy fuel additive (12345515) is Chevron TECHRON Concentrate. These additives reduce knocking if you are octane limited and they are the recommended first step to quiet piston slap. There was a rebate program available from Chevron which saves $2 on the 12 ounce and $3 on the 20 once bottles.

Remember this, Techron is not curing piston slap, it is a knocking noise caused by carbon buildup on the top of the piston, and yes, Techron is an excellent, if not the best product, to remove this buildup (short of a scraper). Some of the Chevy Service Manager(s) don't know the difference of piston slap from carbon knock. Piston slap will go away as the engine heats up, due to the piston skirt expanding. If a service manager can explain how Techron can expand a piston skirt on a cold engine, I would love to hear to tale. So, if someone notices that the noise goes away using Techron, it is a carbon buildup problem, not piston slap. Starting with 2002 cars they used a bigger piston ring to eliminate slap.

In a related area the LS-1 have bad piston slap too, especially when the engine is cold. I think once Joe sees this he will be able to help you out.

[badaz06]

Wow...well...I certainly cant top what Collin has put out...
But my 2001 Conv used to burn oil like it was going out of style...whereas the 02 Z06 seems fine.

[joe1968]

Sorry that it has taken me so long to respond the computers at work won't let me reply on the forum. the "security" system keeps kicking me out. Now about your Vette, first of all congrats on the purchase. I hope you will have many years of fun. Some of the 00 and 01 Vetts had some issues with oil consuption what Chevrolet says is that it is not a problem if it using 1qt or less every 1,000 miles. They will not pay for any internal repairs unless it is using 1qt every 400-600 miles. My take on that is why? I have never recieved a (in my opinion) valid answer... I have been told "the rings take along time to seat,pistions not fitted properly,pcv system design is at fault, 6 speed cars will use more because of running higher RPMs in lower gears ect......" with every person that I have spoken with it is a diffrent answer. So the only thing that I can say is keep track of your usage,make shure that your air filter and pcv valve are clean and enjoy your Vette. If I hear of any fix for the prob. I will post it right away...

Joe

[joe1968]

[quote]Not stealing Joe's thunder, but thought maybe some range of 400-600 miles per quart (700-1000 km/L).

A good,informed answer is never "stealing" my thunder. Thank you. Joe

[Ebein]

Thanks for the replies, im not at the 4-600 miles per quart
( at least i dont think so ) but will start keeping closer
track of my usage