Cadillac Seville / Cadillac Eldorado Forum Discussion, 98 eldorado strange noise on hard acceleration in Past Cadillac Vehicle Discussion; So my 98 has a weird issue. From a dead stop of you accelerate hard is sounds as though the ...
So my 98 has a weird issue. From a dead stop of you accelerate hard is sounds as though the engine is touching the firewall like a metal to metal vibration. Its goes away as soon at the car reaches 10mph or more. It has new dog bones could it be motor mounts?
Re: 98 eldorado strange noise on hard acceleration
Is the catalytic converter (actually the first 5 inches of the exhaust behind the cat) hitting the under body cross brace (one of the 2 you have in that area).
The rear of the cat (and that area of the exhaust) is held in place with 2 rubber "O" rings (you will see them as soon as you get underneath the car).
In time the "O" rings sag and so do the exhaust. If you can't easily slide your finger between the topside of the cross brace and the bottom side of the exhaust then you know the clearance is too small (exhaust too low). In fact grab the exhaust and shake it, you will see it will hit.
Do not replace the "O" rings with nothing but OEM, aftermarket ones (significantly less money) will snap either during the replacement or in the next 10 miles after.