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Document ID: 2355285
#PIP4716: Sharp Engine Noise At Start Ecotec RPOs - LAF LAP LAT LNF LE5 LE8 LE9 - (Oct 1, 2009)

Subject: Sharp Engine Noise At Start Ecotec RPO's-LAF LAP LAT LNF LE5 LE8 LE9

Models: 2009 Chevrolet Cobalt
With RPO LAP 2.2L, LNF 2.0L
AND
2009 Chevrolet HHR
With RPO LNF 2.0L, LE8 2.2L, LE9 2.4L
AND
2009 Pontiac G5
With RPO LAP 2.2L
AND
2009 Chevrolet Malibu
2009 Pontiac G6
2009 Pontiac Solstice
2009 Saturn Sky
2009 Saturn Aura
2009 Saturn Vue
With RPO LE5 2.4L
AND
2009 Saturn AURA Hybrid
2009 Saturn VUE Hybrid
2009-2010 Chevrolet Malibu Hybrid
With RPO LAT 2.4L
AND
2010 Chevrolet Equinox
2010 GMC Terrain
With RPO LAF 2.4L SIDI

The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.
Condition/Concern:

In rare instances a technician may comment they hear a short, sharp rattle noise from the front of the engine on start up.
Recommendation/Instructions:

If the noise is from the front accessory drive area, inspect the engine belt. We have seen concerns with engine belts causing a loud ticking type noise. If found, verify power steering pulley outer edge is aligned flush with shaft and repair as needed. If pulley alignment is correct replace the engine belt.

If the noise is still present and is very short and sharp in duration (2-5 seconds) This may be an issue with the cam phasers not parking properly. Once the noise is verified as the phasers, they must be replaced. If the cam phasers are replaced, remove the CMP actuator solenoids to inspect for debris. If debris is found clean and inspect for torn or loose screens and replace if necessary.

Note: If debris is found in the solenoids and phasers change the oil and filter before returning to service, in some instances it may be necessary to change the oil/filter multiple times with a test drive in between each. The filter and solenoids can be inspected afterwards to ensure no additional debris is present.

Please follow this diagnostic or repair 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.

GM bulletins are intended for use by professional technicians, NOT a "do-it-yourselfer". They are written to inform these technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions, and know-how to do a job properly and safely. If a condition is described, DO NOT assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See your GM dealer for information on whether your vehicle may benefit from the information.


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