Engine - Whistling Noise From Idle to 1,500 RPM
SOURCE: KIA Technician Times Volume 7 Issue 2, 2004TITLE: Engine Whistle
APPLIES TO: 3.5L Sigma Engine
SERVICE TIP:
Under certain conditions a whistling noise similar to a vacuum leak can occur in 3.5L Sigma engines between base idle and 1,500 RPM.
KMA field staff has verified that this concern can be caused by an aftermarket oil filter. The noise may be the result of changed oil pressure/flow interaction between filter and pressure relief valve in the engine oil pump.
If the concern vehicle you are diagnosing has an aftermarket oil filter installed, a check of intake manifold vacuum and short fuel trim readings should be made first to insure there is no vacuum leak causing a concern. Once that is confirmed, replace the aftermarket filter with an original Kia replacement filter and verify that concern is resolved.