i've got a question. About500 miles ago, i got a humm in my radio. It is only with the radio, not the cassette. It is all stock.
The humm goes in time with the rpm's, but only sometimes. I usually get the advice to put a noise suppressor on the 12v "in" side of the radio, but i would like to know what is causing this, not put a bandaid on the problem. Anyone have any ideas? thanks.

 

My thought would be you have a faulty ground connection somewhere in the vehicle that causes a ground loop (which would create the Engine noise).

In fact, it may be something internally in the radio, since you stated it only occurs when your listening to the radio and not the cassette. Does it occur in both FM and AM bands?

Have you tried using a different stereo? know anyone else with the same vehicle as you? maybe you could do a quick swap and see if the problem persists.

 

Try disconnecting the antenna. This may be causing the problem. If it doesn't do it with the antenna disconnected, then you may need to replace it or see if there are any problems with the cable or the mount.

 

Thanks for the info, before ripping my dash apart....It turned out to be rust on both sides of the antenna, both connections I mean.