C5 Z06 Purchase - What to look out for?

[Ed89]

I'm thinking about purchasing an '02-'04 Z06, I would like to know what to look out for other than the norm. Thanks

[ToolGuy]

I know there was a piston ring issue at one time. Not sure if it was a recall or what years. I'm sure if you search the net, you'll find it.

In the mean time, whatever car you are interested in, be sure and get the VIN number. Then go to the dealer and have them put it in the GM system and tell you what kind of history the cars had while under the GM warranty. That will tell you a story if the cars been a good one, or problematic!

Good luck!

[vettespur]

was it not just the 2001 z06 cars that had high oil consumption and I believe there were only a handful.

[ToolGuy]

Here is the complete TSB:

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.

Parts Information

Part Number
Description
Qty

12568002
Valley Cover
1

88984247
Ring Kit, Piston
8



Warranty Information

For vehicles repaired under warranty, use:

Labor Operation
Description
Labor Time

J0250
Manifold or Gasket Intake - Replace Manifold
Use Published Labor Operation Time

J1307
Piston, Rod and/or Rings -- Replace, Both Banks
Use Published Labor Time

[Fixvet]

Originally Posted by Ed89

I'm thinking about purchasing an '02-'04 Z06, I would like to know what to look out for other than the norm. Thanks

Condition, condition, condition, condition.........!! Buy the best car you can for the amount of your budget! I did in 2004 and my '98 coupe was perfect then and still perfect now.....from 19K miles to present 76k miles. I drive it somewhere every week all year around. Never an issue. A Great C5!!

At this point in time, look only for 2004 Z models. All the C5Z bugs were gone by end of the C5Z run.

Good luck

[rocket8189]

Ed89, I envy that you get to search for one of these wonderful cars. I love mine.

I looked and looked and............you get the pic. Bought a 88K '04 C5 Z06, paid KBB for it. Not a regret. Excellent shape, tweeked just like I would have done, no driveline mods and it has been a delight. I've done little to it but replace tires, plugs/wires, fluids, battery, filters and wax it. Did I mention wax it. Torch Red over black and flawless. Recently at a local Route 66 theme resturant, an individual drove up in a re-done '59; parked behind mine. I walked out to admire his ride and he said of mine..."This car is flawless, I can't find a spot on it." They are out there, enjoy the search, hold to your expectations and make the move when all those factors feel right. Have fun. You'll love the car.

Ken

[Ed89]

Thanks Guys