So I took off my heat shield that wraps around my cadillac converter and it still makes the rattling noise like that heat shield would. It's annoying usually happens when I first start the car for a bit goes away and when I accelerate slowly. Any idea anyone ? and if anyone does have ideas please give me details as to where the part is located I am not that car oriented. I was thing the shield that comes off the motor is loose or the plate that covers the exhaust underneath it.

2002 Civic Si Veloz

 

Its catalytic converter, not to be confused with the car manufactuer Cadillac. The best thing you can do is go under the car and have someone start it. It could come from numerous areas along the exhaust. Start from the front and work your way back.

 

on my 01 civic its the bolts on the exhaust that connect to the downpipe that rattle, havent had the energy to go get down there and check it out though. You can have someone turn the car on and see if those bolts start to vibrate when the noise starts. Mine shake like crazy

 

I just got a new motor put in and it happened about a week after. I will go through the process of checking it step by step though. I planned on doing that but I thought there might be someone with the same problem and could pin point a common spot. The problem is it only rattles at certain times not a constant rattle which pisses me off because it would be easier to pinpoint.

 

You have 4 different heat shields, it could be any or all of them. Most common to rot are the shield on the exhaust manifold and the shield above the cat.

 

My friend just had a similar problem with his car. Like the others say, it can be many different things but my friends problem was the honey comb found inside the catalytic converter. they can go bad by all the carbon build-up. It never hurts to check it out

 

my guess since you just had a new engine installed would be to check the engine bay. look for loose bolts, bad mounts, bad belts, and listen for bad components. its old school but if you hold a small diameter metal pipe on the components and put your ear to the end of it (put like a metal funnel or something on the end of it so you dont stab yourself in the eardrum) you can hear any rattles or noises that particular component is making. if you dont have a pipe you can also use a screwdriver the same way. tip to metal ear to handle. also, muffler leaks can sometimes make weird noises which would kind of make sense since you said your noise disappears after everything heats up which would make exhaust components expand a little bit, so as others have said check that front to back. hope it helps.

 

testing it all out today see how she goes thanks for the advice and I will let you know when and if I find the problem.

 

well i still cant find it but i narrowed the vibration down to 2700-2900 rpm in idle

 

My car is making the same noise at the same rpms but i've been to lazy to look underneath, I did the cat a few weeks ago so i'm guessing its a shield or a bolt thats loose on mine