Rattling noise from my Corolla when cold.

[pbm]

My 2008 Corolla has a loud rattling noise on cold start ups. It started last winter and is worse this year (there was no noise during the summer). It seems to change when I put it into gear. It sounds like an exhaust hanger is missing but all looks well underneath the car. My mechanic coworker said it might be the innards of the catalytic converter. I have 65K and should still be covered under the emissions warranty.
If I bring it into Toyota and it's not the CC will they charge me for checking it?
What else could it be?

 

[mclasser]

Have you tried checking if the rattle is from the engine bay? Does your Corolla have a timing chain?

Check for any stored codes related to the cats.

 

[cknight49090]

could be anything a heat shield or anything it needs to be put on the hoist to check.I wouldn't take it to the dealer if its out if warranty unless you have deep pockets.But I wouldn't take it to anybody either you need a small reputable shop.

 

[gregk24]

Sure its not the engine? When you start it up tomorrow open up the hood, listen underneath and all over to try and pin point where the noise is coming from. If it only happens in the winter I would think it would be coming form the engine due to the oil taking longer to make its way around the engine.

 

[pbm]

It's definitely NOT an engine rattle due to oil. I replaced the serpentine belt and tensioner because they are known to cause a rattle but that wasn't it.
It really sounds like the CC shield is loose but when I get underneath I don't see that to be the case.

 

[Rolla07]

Its not the engine and its not underneath? I would jack it up and try to find the noise. Is it sound like creaking towards the back or rattling? I know these cars can rattle at times in various places..chances are they will bill you...personally i wouldnt be too concerned.

 

[Trav]

Get a rubber mallet on the job and hit the exhaust system front to rear.
You will hear the converter, muffler, or heat shield rattle if its loose or inside when you give it a smack.

 

[krismoriah72]

common problems on the corolla are cracked manifolds, look for a hairline crack under the shield. When its very cold the crack is wider than it is when its hot, as the heat expands and fills in the gap in the crack.

If thats not it, look at motor mounts. Since you stated that it gets louder when you put it into gear, the worn or broken motor mount will cause that vibration also.

Both cheap fixes, or could just be a heat shield that is worn out and needs shimmed.

 

[ARCOgraphite]

Do liquid mount freeze in the cold? My Honda sound like a Powerstroke in the winter.

 

[pbm]

Originally Posted By: krismoriah72
common problems on the corolla are cracked manifolds, look for a hairline crack under the shield. When its very cold the crack is wider than it is when its hot, as the heat expands and fills in the gap in the crack.

If thats not it, look at motor mounts. Since you stated that it gets louder when you put it into gear, the worn or broken motor mount will cause that vibration also.

Both cheap fixes, or could just be a heat shield that is worn out and needs shimmed.



I plan on taking Trav's suggestion regarding the rubber mallet.

Where exactly are the manifold's prone to cracking ? I'd like to check this out.

 

[cjcride]

Raise it up, directly behind the resonator there is a flat metal strap held by 2 bolts. I bet it's rattling on the strap.

 

[SatinSilver]

I had a similiar issue on my 05 Matrix and the Corolla has the same problem.

http://www.carcomplaints.com/Toyota/Matrix/2005/tsbs/

Under "fuel tank band" which is connected to the rear heat shield.

 

[PandaBear]

motor mount, I had that problem and it went away after new mounts.

 

[asand1]

Piston slap? How cold is it there?

 

[mikered30]

Intake manifold gasket leak or bad motor mount.

 

[pbm]

Guys...Thanks for all the suggestions. It's definitely not piston slap or even an engine noise. I'll look in to the others. The motor mount is a thought ..

 

[pbm]

Originally Posted By: cjcride
Raise it up, directly behind the resonator there is a flat metal strap held by 2 bolts. I bet it's rattling on the strap.


UPDATE on my original post....I wrapped the 'flat metal strap' with a piece of pipe insulation and was waiting for a very cold morning to see if it helped. Yesterday it didn't rattle and today, at 6*F, it didn't rattle. I think I found my problem ...I now have to find something better (more resistant to the heat of the exhaust longterm and try to make a permanent fix.)...any suggestions?

PS: The Corolla still isn't the quietest car on cold start up (NVH) but it seems that
I may have solved the 'rattle' problem. Thanks cjcride

 

[cjcride]

Originally Posted By: pbm
Originally Posted By: cjcride
Raise it up, directly behind the resonator there is a flat metal strap held by 2 bolts. I bet it's rattling on the strap.


UPDATE on my original post....I wrapped the 'flat metal strap' with a piece of pipe insulation and was waiting for a very cold morning to see if it helped. Yesterday it didn't rattle and today, at 6*F, it didn't rattle. I think I found my problem ...I now have to find something better (more resistant to the heat of the exhaust longterm and try to make a permanent fix.)...any suggestions?

PS: The Corolla still isn't the quietest car on cold start up (NVH) but it seems that
I may have solved the 'rattle' problem. Thanks cjcride
Glad to be of help PBM. I used metal washers to 'buy' more play room for the exhaust pipe. Was going the same route as you initially. The heat problem steered me to the washers.