1976 Eldorado- very loud when first idling

[LenInLA]

When I first turn the car on and it idles, the engine is very loud - loud enough to interfere with conversations. As soon as I put the car in drive, the noise disappears. The noise seems to be worst after the car has been standing for a couple of days.

Any ideas?

Thanks!

Leonard Grayver

[The Tassie Devil(le)]

If it is an exhaust noise, it could be that when cold, there is a hole, and as it warms up, the heat closes up the hole?

Plus, if the noise is the exhaust banging under the car, when you put it into drive, it applies a rotational force to the engine/trans.   Does the noise stop?   This could be the result of a damaged engine/transmission mounting?

A bit hard to diagnose without hearing it.

Bruce.

[TJ Hopland]

You sure its not something like the alternator belt slipping at first? 

Warmed up there is no noise in park? 

Exhaust was a thought if its fine warmed up.     IF its still there warmed up then I was thinking maybe a cracked flexplate.   

[LenInLA]

I checked and the alternator belt is loose. I'll replace it and see if it solves the problem!

Thanks for the advice!

Leonard Grayver