Engine Valve Train - Noise
89cadillac13Bulletin No T-90-9
File in Group 6A
Number 107
Corp. Ref. No. 106107R
Date Oct. 1989
SUBJECT: VALVE TRAIN NOISE
MODELS AFFECTED: 1988-1989 DE VILLES, FLEETWOODS, ELDORADOS, AND SEVILLES 1987-1988 ALLANTES
This bulletin supersedes bulletin T-89-83, Group 6A, which should be discarded.
Some 1988-1989 DeVilles, Fleetwoods, Eldorados, and Sevilles and 1987-1988 Allantes may experience a valve train speed noise most often described as "lifter noise" or "lifter tick". Typically this noise is loudest when the engine is started cold and gets quieter as the engine reaches operating temperature but never quite disappears. It is most noticeable at idle, particularly when a nearby object reflects the noise.
To repair this condition on 1987-1988 Allantes and 1988-1989 DeVilles, Fleetwoods, Eldorados, and Sevilles, install a set of revised rate valve springs, P/N 1649686 (16 required). These third design springs are used in 1990 DeVille, Fleetwood, Eldorado, and Seville production engines. The 1989-1990 high output Allante engine uses a unique valve spring.
Parts are currently available from GMSPO.