Engine - Whistling or Whining Noise
Bulletin 86-6-18Date June '86
Ref. No. 86-104-6
SUBJECT: WHISTLING OR WHINING NOISE FROM ENGINE ASSEMBLY
MODELS AFFECTED: 1986 CENTURYS & LESABRES EQUIPPED WITH 3.8L V-6 (VIN CODE 3) ENGINES
If a whistling or whining noise, that sounds somewhat like an intake air leak, occurs on one of the above vehicles up to approximately 2500 rpm, the intake manifold sealing areas should be checked for leaks. This can best be accomplished using a plews type oiler, or some other similar tool, and applying a small amount of oil or water to the intake manifold sealing surfaces. If the noise is still evident, the Serpentine belt should be removed and the engine run again. If the noise is still audible, the camshaft should then be inspected.
CAMSHAFT:
If inspection reveals minute flat spaces or ridges on the lobes of the camshaft that look like those in the illustration, replacing the camshaft should eliminate the noise.