lately when i start my car i hear a really loud rattle coming from the engine. The rattle only lasts about 3 seconds. The rattle isnt there EVERYTIME i start my car but at least once or twice a day it makes the rattle for just a few seconds. I booked an appointment to take it in to my dealer. What do you guys think it could be??

 

Timing chain maybe? or it may just be the parts in your valve train that aren't quite oiled up yet.

 

could be this

#PIP4716C: Sharp Engine Rattle Noise At Start Up May Also Set P0011 P0014 P0016 P0017 - (Aug 2, 2011)

Subject:
Sharp Engine Rattle Noise At Start Up may also set P0011 P0014 P0016 P0017

Models:
2010 Buick LaCrosse
2009-2010 Chevrolet Cobalt
2010 Chevrolet Equinox
2009-2010 Chevrolet HHR
2009-2010 Chevrolet Malibu
2010-2010 GMC Terrain
2009-2010 Pontiac G5
2009-2010 Pontiac G6
2009-2010 Pontiac Solstice
2009-2010 Saturn Aura
2009-2010 Saturn Sky
2009-2010 Saturn Vue

Equipped with the following engines
2009-2010 2.0L (RPO LNF)
2009-2010 2.2L (RPO LAP/LE8)
2009-2010 2.4L (RPO LE5/LE9/LAT/LAF



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This PI was superseded to remove 2011 model years. Please discard PIP4716B.
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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 at start up. P0011 P0014 P0016 or P0017 may also set during this condition.

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 solenoid 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 one. 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.

 

I see this daily now... Most likely what frossb said

 

i looked at a bunch of videos online and it sounds like Cam Phasers....what is a cam phaser???

 

Cam phasers are what control the variable valve timing

 

what would happen if the dealer does not hear the rattle on start up?? If it is the cam phasers what would happen if they dont get replaced? can it cause any harm?

 

????

 

Mine rattles but its my exhaust lol

 

Check out videos w bad timing tensioners