Engine - Blue/White Smoke On Startup

89chevy05

GMC NUMBER: 88-T-195


GROUP: 6A - Engine Mechanical

DATE: February, 1989

CORPORATE
NUMBER: 836546R

SUBJECT: BLUE/WHITE SMOKE ON STARTUP

MODELS: 1987-88 C/K/R/V/G AND P TRUCKS W/5.0L AND 5.7L (VIN CODE H AND K) ENGINES

Some vehicles may exhibit a puff of blue/white smoke on startup which is difficult to diagnose. Some hints on diagnosis and recommended corrective action are listed below:
Throttle Body Injection (TBI) Trucks If the smoke is white or bluish white, occurs only at startup, and no unusual oil consumption is noted, then the joint between the intake manifold and the cylinder head may be suspect. The intake manifold bolt torques should be checked. The intake manifold bolts (particularly the two bolts nearest each corner) should be removed and the inside of the bolt holes in the manifold should be inspected for signs of threading (grooves cut in the manifold by the bolts). If several of the intake manifold bolts have very low torque (10 ft.lbs., or less) and/or the manifold bolt holes show signs of threading, the intake manifold should be replaced with the appropriate service manifold from the table below:

Engine Intake Manifold P/N
All (5.0L and 5.7L) TBI 14102183

Parts are currently available from GMSPO. If no evidence of manifold threading is found, and the smoke on startup is definitely of a bluish nature or if there is also a comment of oil consumption, the exhaust valve guide clearance should be checked for excessive clearance using the procedure outlined in Section 6A of the appropriate Service Manual.

Use the following labor operations and times:

J0200 Replace Intake Manifold C/K - 2.0 Hrs
R/V - 2.2 Hrs
G/P - 2.7 Hrs

Add for Air Conditioning C/K/G/P - .2 Hr
RV - .1 Hr

Cruise Control G/P - .2 Hr
RV - .1 Hr