Rattling from under engine...likely culprits?

toronto_1990sc

Registered User
there's a new rattling i heard when driving...i parked and listened while it idled...i hear it most loudly from below, under the engine..less loud from above as the engine noise drowns it out...sounds like its coming from somewhere under the engine, a fast metallic rattle. always embarrasing driving around with a rattle.

loose exhaust part? loose heat shield? something worse?
 
Do you have headers?? My friends GTO with headers would pick up all kinds of crazy things and they would sit and rattle where the 4 pipes join into the collector. It would only be at certain RPMs and at idle.
 
If its an automatic, I would look at the torque converter nuts to see if one has come loose and is rattling around in the bell housing. May also be some sort of debris in there. Hard to say without hearing it. If the rattle increase in frequency with RPM than it is probably something internal to the engine or transmission. If the rattle gets less as RPM increases, than its probably something loose and vibrating against something metallic.

Mark
 
If its an automatic, I would look at the torque converter nuts to see if one has come loose and is rattling around in the bell housing. May also be some sort of debris in there. Hard to say without hearing it. If the rattle increase in frequency with RPM than it is probably something internal to the engine or transmission. If the rattle gets less as RPM increases, than its probably something loose and vibrating against something metallic.

Mark

thanks. yep its an auto...rattle seems to be fairly constant, hard to tell.

i guess i'll have to get my guy to check it out when i get my oil changed. cant really get under the car on my own.
 
It isn't uncommon for the insides of a catalytic converter to come loose and cause the sound you describe. Put the car up on ramps/jack stands and listen from underneath.

Bryan
 
It isn't uncommon for the insides of a catalytic converter to come loose and cause the sound you describe. Put the car up on ramps/jack stands and listen from underneath.

Bryan

That's what my rattle was from. After removing the middle cat I found the chunks and powder that were circulating around. There's a thread started by me on here about it with pics.
 
could also be your harmonic balancer. the one in my 95 failed (albeit discreetly thankfully) and the balancer outer ring was contacting the timing cover causing a rapid rattling or 'clicking' noise that increased with rpm.
 
"there's a new rattling i heard when driving...i parked and listened while it idled...i hear it most loudly from below, under the engine..less loud from above as the engine noise drowns it out...sounds like its coming from somewhere under the engine, a fast metallic rattle. always embarrasing driving around with a rattle.

loose exhaust part? loose heat shield? something worse?
Smurfs
 
If it is a loose heat shield on your cats, go to home depot and buy a couple of extra long hose clamps. Wrap them completely around the loose heat shield and cat and tighten them up. Cut off any excess and your good to go.
 
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