Exhaust - Blue or Bluish White Smoke On Startup

91chevy27

GMC NUMBER: 91-6A-167

GROUP: 6A Engine Mechanical

DATE: December, 1991


CORPORATE NUMBER: 136007


SUBJECT: TAILPIPE SMOKE ON STARTUP (INSTALL NEW VALVE STEM SEAL KIT)

MODELS: 1987-91 C/K AND R/V/G/P MODELS WITH 5.0L AND 5.7L ENGINES


THIS BULLETIN CANCELS AND SUPERSEDES GMC TRUCK BULLETIN 89-6A-109, OCTOBER 1989 (CORPORATE BULLETIN # 836546R) AND GMC TRUCK BULLETIN 90-6A-80, JULY 1990 (CORPORATE BULLETIN # 066102). ALL COPIES OF THE ABOVE BULLETINS SHOULD BE DISCARDED.

Some owners of the above vehicles may comment on a puff of blue or bluish white tailpipe smoke on startup. This may be caused by oil leaking past valve stem seals and being deposited on exhaust valve(s).


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.