Models affected: 2004-2005 Cadillac CTS, SRX; 2005 Cadillac STS with 3.6L Engine (VIN 7 – RPO LY7); and without Heavy Duty Cooling (RPO V03tV92).

This bulletin has been revised to add additional information on inspecting the crankshaft harmonic balancer. Other complaints of a faint engine whine-type noise have been reported at speeds of 0-30 mph (0-48 km/h) at 1,000-2,500 rpm and may be caused by the primary camshaft drive chain. This type of noise may be amplified by the vehicle’s body structure.

Condition
Some customers may comment on a whine-, whistle- or ringing-type noise from the front of the engine that increases in intensity as engine rpm increases. This noise is most audible standing in front of the vehicle with the hood opened. If the noise fades into the ambient engine noise by 2,000 rpm the harmonic balancer may be the culprit.



Cause
This condition may be caused may by the harmonic balancer. This bulletin is being revised to add additional information on inspecting the crankshaft harmonic balancer. Refer to Figure 1 and inspect the crankshaft harmonic balancer for design type. After the inspection, if the vehicle was built with three-spoke design crankshaft harmonic balancer, replace the harmonic balancer with p/n 12597654.

Correction
If the vehicle is equipped with the V03N92 Heavy Duty Cooling package, DO NOT replace the six spoke design crankshaft harmonic balancer (see Figure 2). Continue with routine diagnosis to isolate the noise.

Some or all of this information was provided by the Automotive Parts Remanufacturers Association (APRA). For more information on technical bulletins available through APRA call 703-968-2772 or visit www.AutoBulletins.com.