Sound problem...

[00FlowCamaro]

So here's the deal...

My car makes this noise, it only does when it is under torque like going up hills and etc and at a low rpm 99% of the time. Late November i put on a Flowmaster American Thunder exhaust and ever since its been making this noise under those conditions. There is nothing touching anything along the Exhaust track and the clamps are tighter than hell ( I should know ). My dad has had XX number of cars that he has built and worked on and he doesnt know what the hell it is and neither does my uncle who is a mechanic. I've narrowed it down that it shouldn't be anying from the cat up because my original exhaust had no problem with any noises, but the noise does sound like it is either coming from the cat or from under the hood. It is hard to tell because you have to be actually driving the car to hear it :spank:

The noise sounds like more of a metal on metal noise (more like tin, doesnt seem like the heat guards should be the problem because ive tested non rattling material between them and the body and no change)
When you're driving it, it also sounds like a hard air leak, dirty sounding.

If this helps..I've replaced the alternator and they put on a new built and battery when i got the car.

Any suggestions whatsoever would help so much.

[BLLDOGG]

Re: Sound problem...

are you maybe describing an exhaust leak?

[00FlowCamaro]

Re: Sound problem...

I asked my dad about that, but it sounds like more of a rattle when it hits the real big trouble. Again, im not sure if its something like maybe my cat took a crap, I had a pipe made to replace the cat, just waiting for warmer weather to install it. But yes, sometimes when you listen it does sound like a hard dirty air flow. I just couldn't find anywhere it could be leaking, I've been over and over the car for months now. Know of anyway i could find out if it is an air leak?

[BLLDOGG]

Re: Sound problem...

I can not think of any safe way to do it other than just the plain old way of feeling around. It maybe hard to find in your driveway since it seems to leak only under a load. I wouldn't recommend laying under the car with someone loading the engine down.

[00FlowCamaro]

Re: Sound problem...

A quick question, would an air leak sound like a rattle somewhat if under torque and at a low rpm?

[BLLDOGG]

Re: Sound problem...

it could because of the pulses of the exhaust. might sound like rhythmic instead of a solid sound.

[00FlowCamaro]

Re: Sound problem...

So I'm going to try and get a sound clip of it...it is the most awkward sounding thing...for the moment im going to make sure all my clamps and every pipe is banged tight just to be safe...Hopefully I'll get that sound clip soon and someone can hear it out.

[BLLDOGG]

Re: Sound problem...

personally, I wouldn't waste your time on a sound clip. really is not an effective way to find a problem. it is about the hardest over the internet to do is diagnose a sound

[00FlowCamaro]

Re: Sound problem...

I was just browsing under my hood and everything. The only couple of things I can think of that would make it would be:

One of the heat shields (already took one off on a header for the problem)
We put on a new Alternator (maybe its not on totally right and the belt is screwing with it under torque)
There is an apparent leak (dad is sure its antifreeze fluid, not sure what that has to do with a noise, maybe a cracked hose)

Maybe something of that can tip you off, I was just all around the exhaust line searching for probable exhaust leaks...and nothing. That would occur all the time, I would think, if the engine is running or not. This noise will not be made by revving the engine in Park or Drive. Hell, I've even tried when the noise was being made, dropped it into N and revved the engine...it seems it will ONLY do it if its in gear and under some kind of torque or low rpm. Another thing...seems to do it worse when cold and when the problem starts it seems to do it more often.

[BLLDOGG]

Re: Sound problem...

try getting your dad to get out there when the engine is cold, put it in drive and hold the brake down and press the gas to load the engine down while you are standing to the side with your head buried in the engine bay. or other way around. its not uncommon to have aleak with just the engine loaded or cold. when everything heats up, metals expand closing small leaks and also, when not under a load, its easier for the exhaust to flow out normally than through a small leak. good luck

[00FlowCamaro]

Re: Sound problem...

Thanks for all the advice. This weekend I'll tell him whats up and what you said and give it a try. Would it be possible to have an exhaust leak between the header and where it is connected to the engine, even though it came from the factory? I understand mine is already 7 years old and it could have more serious problems.

If nothing seems to work in the next couple of weeks I'm just going to put the original exhaust back on and take it from there.

[00FlowCamaro]

Re: Sound problem...

Also, sorry again for another, possible problem. Torque Converter maybe?

[BlackCamaro581]

Re: Sound problem...

So here's the deal...

My car makes this noise, it only does when it is under torque like going up hills and etc and at a low rpm 99% of the time. Late November i put on a Flowmaster American Thunder exhaust and ever since its been making this noise under those conditions. There is nothing touching anything along the Exhaust track and the clamps are tighter than hell ( I should know ). My dad has had XX number of cars that he has built and worked on and he doesnt know what the hell it is and neither does my uncle who is a mechanic. I've narrowed it down that it shouldn't be anying from the cat up because my original exhaust had no problem with any noises, but the noise does sound like it is either coming from the cat or from under the hood. It is hard to tell because you have to be actually driving the car to hear it :spank:

The noise sounds like more of a metal on metal noise (more like tin, doesnt seem like the heat guards should be the problem because ive tested non rattling material between them and the body and no change)
When you're driving it, it also sounds like a hard air leak, dirty sounding.

If this helps..I've replaced the alternator and they put on a new built and battery when i got the car.

Any suggestions whatsoever would help so much.

I had a similar problem, I installed a dynomax and it turned out to be two things. One, the tips were too short,(lost back pressure) and as a result it caused my muffler to vibrate producing that awful noise right after turnover, and like you said under low torque conditions. For me, re-tightening all the bolts and lengthening the tips cured the problem. The tips are 2.25@18in long, dual out. They were less than 1/2 the length before. Good Luck

[00FlowCamaro]

Re: Sound problem...

My dad said it would make perfectly good sense that being the problem. So me and my dad will mess with the tailpipes this weekend to maybe cure it, if that is the problem(hoping it is). Thanks :)

[silvachris1]

Re: Sound problem...

Before you start hacking up your new tips, check the catalytic convertor first. Just get under the car and hit the cat about 10-15 times in different locations and with different forces, see if you're rattle is inside there. If it's not, then check the other ideas you've read. I had an insanely aggrivating rattle sound under my car at low rpms just cruising around and when I'd go up hills and stuff. I was trying to check the heat shield above the cat and accidentally hit the cat instead, and found my rattle. After having it replaced, we found that a big chunk of the cat ad just broke off inside. Like a 3"x3" square section, and it couldn't pass through the exit on the cat. :Rattle: :Rattle: