Engine Noise Problem

[el_Don]

I'm having some engine noise that started yesterday on a trip home. The noise sounds like the noise that is made when you attach a baseball card in a position to make contact with the spokes of your bicycle. The sound cannot be heard when the engine is at a constant speed, but only when I'm accelerating. The noise gets "faster" as the rpms increase. It doesn't seem that there's anything wrong with the car, no performance decrease or anything. I'm thinking that it might be a problem with the exhaust, maybe a crack, I don't know.

Anyone have an idea how I can find out? Thanks (thumb)

 

[derfernerf]

is the CEL on? you can diagnose it from there usually. if not, figure out were the sound is coming from. i have the same problem, and its from a crack in my header. so visually inspect everything, if you dont find anything, then figure out if the noise is coming from inside the engine, or outside. and go from there

 

[el_Don]

No CEL. I think my header is cracked too but I'm looking for a way to be sure, there's an area that I can't see a crack in because of the angle. Anyone know of some way to detect exhaust leaks?

 

[derfernerf]

well the first key sign of an exhaust leak is the smell. then, you can either take it off and visually inspect it, or get a mechanics stethoscope and find a leak that way. if using the stethoscope, it helps to have someone or something plug the tail pipe. it will force more exhaust out of the crack making it easier to find. hope this helps!

 

[ucMP3]

A crack in your manifold or something similar can make the already noisy valve train & lifters even louder.

 

[el_Don]

A crack in your manifold or something similar can make the already noisy valve train & lifters even louder.

Yeah, I think that's what I'm hearing. Really my main fear is that I'm actually damaging the engine every time I turn it on and use the car. I really don't smell anything that I can recall. The exhaust note of the car has changed significantly though. I'm guessing that Christmas will be spent inspecting the exhaust of the car.

 

[ucMP3]

Yeah, I think that's what I'm hearing. Really my main fear is that I'm actually damaging the engine every time I turn it on and use the car. I really don't smell anything that I can recall. The exhaust note of the car has changed significantly though. I'm guessing that Christmas will be spent inspecting the exhaust of the car.

I doubt you'd be able to smell that small of an exhaust leak... You *may* be able to feel it, but by what you've said, I would guess you won't be able to...

You said that you only heard the noise under acceleration right? I would guess this is because the crack is holding pressure until you gas it and the leak shows itself while under load.

Does that make sense? Sorry I'm bad at English/communication, as others on the forums will gladly attest to, lol.

 

[el_Don]

I doubt you'd be able to smell that small of an exhaust leak... You *may* be able to feel it, but by what you've said, I would guess you won't be able to...

You said that you only heard the noise under acceleration right? I would guess this is because the crack is holding pressure until you gas it and the leak shows itself while under load.

Does that make sense? Sorry I'm bad at English/communication, as others on the forums will gladly attest to, lol.

I can faintly hear it with the engine is at idle, but when I'm accelerating it becomes much more prominent. Also, I notice that when I'm at a constant speed like 60 on the highway for example, the sound is much less. However, if I want to take someone over, then I'll hear it as I'm putting more gas or downshifting.

 

[derfernerf]

yep, ive got the same problem...and i can clearly see my header is cracked. so that could very well be your be problem. good luck with your problem, hope you get it worked out

 

[ucMP3]

I can faintly hear it with the engine is at idle, but when I'm accelerating it becomes much more prominent. Also, I notice that when I'm at a constant speed like 60 on the highway for example, the sound is much less. However, if I want to take someone over, then I'll hear it as I'm putting more gas or downshifting.

Ya, the crack expands while the motor is under load becuase there are much more exhaust gases and pressure being exerted on the crack.

 

[el_Don]

Took off the header and found that it was indeed cracked. Replaced the stock exhaust manifold and now I'm back in business. Will get the header welded and upgraded.