1987 - 1991 Corvette: Service Bulletin: Tail Pipe Smoke on Startup

Subject: TAIL PIPE SMOKE ON START-UP (INSTALL NEW VALVE SEAL KIT)
Model and Year:
1987-91 CAPRICE, CAMARO AND CORVETTE WITH 5.0L AND 5.7L ENGINES
1987-91 C/K, RN, G AND P TRUCKS WITH 5.0L AND 5.7L ENGINES
Source: Chevrolet Service Bulletin
Bulletin Number: 91-449-6A - (11/12/1991)

THIS BULLETIN CANCELS AND SUPERSEDES DEALER SERVICE BULLETIN NO. 89-314-6, DATED JULY 1990 AND 90-300-6A, DATED JULY 1990. THE CAUSE AND CORRECTION HAVE BEEN REVISED. ALL COPIES OF 89-314-6 AND 90-300-6A SHOULD BE DISCARDED.

CONDITION:

Some owners of the above vehicles may comment on a puff of blue or bluish white tailpipe smoke on startup.

CAUSE:

Oil leaking past valve stem seals and being deposited on exhaust valve(s).

CORRECTION:

A new valve stem seal kit (P/N 12511890) has been released to address this concern. The kit incorporates a new umbrella seal with a "viton" insert for the exhaust valve stem.

Parts are currently available from GMSPO.

Use applicable labor operations and times.

General Motors bulletins are intended for use by professional technicians, not a "do-it-yourselfer". They are written to inform those technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions and know-how to do a job properly and safely. If a condition is described, do not assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See a General Motors dealer servicing your brand of General Motors vehicle for information on whether your vehicle may benefit from the information.