Hello,
Recently, in my 1994 Ford E150 van, a high-pitched whining or singing noise has developed. It seems to emanate from the general engine area. It comes and goes, and has a pure-toned frequency that is porportional to the engine speed. I would guess that the sound has a waveform that is a fairly clean sine wave.
Most of the time it is silent, but then it is there, sometimes loud, sometimes soft. It seems to go away when the engine is laboring, as in accerlerating or in going uphill. Perhaps the sound is there more often when the engine is cold.
When I took the van to a mechanic, the sound did not happen, so I have no diagnosis for it. Does anyone have an idea what this sound might be?
If you answer email, please send to robert1111 AT starcenter.com .
Thank you.