02 VIN S 4.2 LL8 Engines - Squeak or Whistle While Driving - kw air hose intake low manifold noise resonator speed whine

The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in the PI.

Some 2002 Models equipped with the VIN S 4.2L engine may experience a squeak or whistle noise while driving at operating temperature. Typically, this noise is not present at low vehicle speeds, low engine rpm or when the engine temperature is cold and it sounds similar to a brake pad wear indicator contacting a brake rotor.

If the SI diagnostics do not isolate a cause, inspect the inside of the crankcase vent port on the right front corner of the air cleaner resonator for a casting flash. The second picture down in SI document 734655 shows where the crankcase vent hose (Item 1) attaches to this crankcase vent port. If a casting flash is found inside of air cleaner resonator crankcase vent port, remove the casting flash and reevaluate the noise.

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Please follow this diagnosis process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed.

(02 Chevrolet TrailBlazer) and (02 GMC Envoy) and (02 Oldsmobile Bravada)

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