Strange noise when starting cold

When starting in morning (even if weather is warm) or after car has sat for several hours, my 1999 Taurus makes a high-pitched whirring noise. Thought it was a loose fan belt, but mechanic said that was wrong. Have taken it to several mechanics and, of course, it doesn’t make the noise after I’ve driven it there. Have to leave it overnight, which is HUGE problem as I don’t live near public transportation. Noise occurs several times as I shift into DRIVE and then accelerate. After that, it disappears, then comes back again, if I leave it sit for several hours. One mechanical friend checked the tranny fluid and said it’s fine. Also said it is probably not the tranny but didn’t know what it could be. i took it to one of your recommended mechanics, but they couldn’t find anything and said they didn’t even hear the noise, although I did leave it overnight at their garage. (Won’t go back there again.) Any suggestions?

Probably a belt is slipping, loose or glazed. Could be a bearing on the pwr steering, tensioner or A/C, but I would bet a belt. Pour water on the belts when it is making the noise. This should quiet it down and prove the belt theory.

I had a similar problem. Sounded like a tuning fork almost then quiet then tuning fork again and quiet. Had 60 miles to go and at about 50 miles I realized my alternator had died. Last 10 miles at night Christmas Eve in the Rocky Mountains zero degrees I shut off all electrical non essentials and made it home on battery power running the headlights and fuel pump.

It may be the belt. Although belt dressing wont cure a belt problem it can identify whether the belt is the source of the noise. Spray belt dressing on a stretch of the belt, top and bottom, and on all the pulleys that are accessible prior to a cold start and when the engine starts pay attention to any change in the noise.

If the noise is a squealing screeching noise similar to a belt squeak, if the noise changes in pitch or frequency along with engine speed, and sounds like it’s coming from the rear of the engine (not the end the belts are on), the problem is likely the camshaft synchronizer. This part goes where the distributor used to be located, and is now used to drive the oil pump and camshaft sensor. The synchro wears internally and makes a noise almost identical to a slipping belt.

I recently had a similar problem in my 05 Taurus. Eventually the noise went from sometimes to all of the time. It was the lower pulley running the serpentine belt. I replaced the belt and pulley. If the noise is coming from near the area of the alternator and belt, have a mechanic check the pulleys. For the lack of auto repair vocabulary, the mechanic used a “stethoscope” type tool to place on the pulleys to locate the origin of the noise. Good luck.