Dayton Daily News

Wheels:Günther writes, “My wife Karen drives a 1996 Toyota Camry LE 4-cylinder, with 167,000 miles. About a month and a half ago, Karen complained about a nasty high-pitched whistling sound coming from her engine compartment. I had a look at it but couldn’t identify the source of the noise. Therefore, I asked my longtime mechanic (for more serious problems) to have a look. He felt the generator is the culprit.

Because the driving belt looked worn and I wanted to rule out a driving belt problem (just to be sure), I exchanged the old belt with a new one. However, after the exchange, I did not have an opportunity to drive the car and my wife said the whistle is back.

This time I let another shop have a look at it. This time the mechanic felt it is the (new) driving belt and applied some grease to the belt. (Halderman note: Grease should never be applied to an accessory drive belt.) The whistling was gone — at least for a while. About a month or so later, as I checked the car over, the whistle is back. It is a very high-pitched whistling sound.

Interestingly, when I apply belt dressing to the driving belt, the whistle completely disappears but only for a minute or so. I found a long, solid screwdriver in my garage and did the listening on my own. I can’t tell if the source of the noise is the generator or the A/C compressor. I can tell, however, that the noise is the strongest at the right end of the A/C compressor casing (the side opposite to the driving belt side) or when I listen close to the space behind the right front wheel. Very confusing, isn’t it? The noise could come from two sources, the driving belt and the A/C compressor (clutch?). Any suggestions?”

Halderman: Noise is often difficult to pin down, so I am not surprised that it is giving you some concern. Some thoughts:

1. You have not mentioned the timing belt or the idler pulleys that drive the camshaft. These could be the problem, and the noise goes away because you are changing (slightly) the crankshaft drive pulley.

2. I spray water from a spray bottle on the belts with the engine running. If the noise goes away or changes, then I know it is belt- or pulley-related. Your belt dressing seems to indicate the same results.

3. The pulleys must be carefully inspected for small bits of rubber from the belt.

4. The belt could be misaligned. Carefully check that all of the pulleys are in line.

5. The idler pulley could be defective. Try removing the belt and spring from the idler pulley and check for noise.