Lately I've heard sort of a low pitched noise on my 1994 940 wagon (non-turbo). It's not very loud, in fact if the radio's on you can't hear it.

Best way I can describe it is to put your mouth in the shape of an "O" and vibrate your vocal cords from deep down. Like a HuuuuuuuuuuuuuuuuuuuuuuuuuuuuH.

Seems RPM sensitive from inside the car. Opened the hood today an heard it plainly at idle (but did not have a stethoscope or tube to try to pinpoint the source, almost seemed to come from underneath rather than from the engine bay)

Where should I start looking?


TIA

 

Start looking at the heat sheilds on the down pipe from the manifold.
If the heat sheild is rattling you can remove it and toss it in the garbage.