Was it determind that the 1-2 second noise at cold start up that sounds a lot like someone shaking a metallic rattle can super fast was the cam phaser sensors or the timing chain tensioner??? I guess another way to describe the sound is almost like when you wind up a pull-back car really far and let it go... Or like a strange aaooogah noise....? I dunno.

I've gotten the noise 2 days in a row now and it's pissing me off.

No codes no cel. Brand new oil from about 150 miles ago using Pennzoil Ultra 5W30 and a Mobil 1 filter.

 

From what I have read, its the cam phasers not "parking" properly.

My '08 has started doing it now that the weather is cold, on a cold start you can hear the metallic rattle for 1-3 seconds and the idle dips and recovers. No CEL on my car either.

According to GM's TSB, the cam phasers need to be replaced in order to correct the noise. Guess I'll have to bring it in for service.

 

If you like, please let me know when you decide to go in. I'm available to assist as best as I can!
Sarah
GM Customer Service

 

Thanks, I will let you know.

Would you be able to tell me if the powertrain warranty covers an exhaust leak at the turbo?? I have a bad ticking/exhaust leak sound under a load coming from the turbo/exhaust manifold area, and its expecially bad when cold.

 

The following components are covered, per the 2008 Chevrolet Warranty Manual:

Engine: Cylinder head, block, timing gears, timing
chain, timing cover, oil pump/oil pump housing,
OHC carriers, valve covers, oil pan, seals, gaskets,
turbocharger, supercharger and all internal lubricated
parts as well as manifolds, flywheel, water pump,
harmonic balancer and engine mount. Timing belts are
covered until the first scheduled maintenance interval.
Transmission/Transaxle/Transfer Case: Case,
all internal lubricated parts, torque converter,
transfer case, transmission/transaxle mounts, seals,
and gaskets.
Drive Systems: Final drive housing, all internal
lubricated parts, axle shafts and bearings, constant
velocity joints, axle housing, propeller shafts, universal
joints, wheel bearings, locking hubs, front differential
actuator, supports, front and rear hub bearings,
seals and gaskets.

As the turbocharger is included on the list, it is definitely possible that the repair would be covered; however, the dealer will need to diagnose the cause behind the sound you're hearing, which will determine whether or not the repair falls under this warranty.

I hope this is helpful for you,
Sarah
GM Customer Service

 

mine does these same noises, so i should get it checked out. mine doesnt do it all the time tho

 

Mine doesn't either, mostly when its cold and after its been sitting overnight is when its most noticeable.

The noise doesn't cause any damage, its the root of the noise thats the concern. The cam phasers are supposed to "park" after shutdown, probably at zero degrees advance/retard. Apparently some phasers are having problems with doing that, which results in the metallic rattle as oil prossure reaches the actuators and they jump to whatever timing position they are supposed to be at during cold start/cat warm up mode.

Its one of those issues that probably won't ever cause any real problems since the phasers seem to work fine once they recieve oil pressure, but if you are under warranty, might as well has it addressed now instead of taking the chance of having an issue later on.

 

this happened to me the other day n i freaked out. is it a lot of work to fix the problem

 

does this noise come from between firewall and engine on drivers side??

 

Is this rattleing at startup a TSB? Should we bring it in for warrantee service Sarah?

 

Good morning quickboat,

Unfortunately, I don't have access to TSBs at this time. As for whether or not a repair on this rattling concern would be covered under warranty, this depends upon whether the root of the concern is diagnosed to be an item covered by the powertrain warranty if the vehicle is older than 3 years old (I included a list of those components earlier in the thread).

I hope this helps to clarify. If I can answer any further questions please let me know!
Sarah
GM Customer Service

 

I guess it would be part of the "all internal lubricated parts". Its not hurting performance now but I wonder if a failure will occur in the future due to oil starvation of that part. I will inquire to the dealership. I just hate to be out of a car for days at a time.

 

Cobalt SS/TC cold start with a rattle/funky sound - YouTube

does it sound like this???

mine made this noise. i dropped it off at the dealership after about 2 weeks they replaced the tensioner/timing chains/cam actuators/cam phasors/timing chain guides.

noise is gone. once and a while i will hear the noise but not nearly as bad as the noise herd in the video.

 

Keep me posted, quickboat. I'm available to help if need be!
Sarah
GM Customer Service

 

Get it checked out. Mine was making this noise for a while... it's now sitting in the driveway because the timing chain broke. It's an issue with the tensioner, not the phasers.

 

Mine is a loud rattling for a few seconds at startup, but not everytime you cold start it. So you know when its brought to the dealer it wont do it and they will look at me with deer in the headlights.

 

im no mechanic however sounds like turbo surge. u have aftermarket pipes? i say this bc that is very common on pipeing changes on th TC .

 

Definitely not surge. That's exactly what my car sounded like, except it didn't have quite as much delay before the noise at :25. I believe that is the tensioner pumping up. After that event the car sounds completely normal. Prior to that event it rattles (chain slapping guides), like an older car on dry start without an anti-drain back oil filter.

 

nope. all stock. sense then its been fixed.

 

Weird noise. Never had that issue with either of my TCs. Now when I had a bad leak in my piping on cold start ups it would make a noise sort of like that when it would about stall out.

 

all stock, i would keep an eye on it, compressor surge is baaaaaaad. glad to hear it went away tho

 

That is the exact noise that my '08 SS makes on startup.

 

when i took it to the dealership (for the 2nd time) the techs finally heard the sound. the tech looked at my like i had a big ***** on the top of my head when i told him it was only a cold start noise.

in that video my car was all stock besides muffler delete and a K&N drop in.
since that video ive gone GMS1,K&N typhoon and cat back. i dont hear the noise anymore cause i watch it closely when i warm my car up for a minute or 2 before heading to work.

damn K&N sounds like a jet on a cold start

 

Are cam phasers covered under warrenty i have extended warranty and powertrain warranty????