this might be a dumb question, but what does a alternator belt (at least I think that is what it is) that make a short 'squeal' every 3 or 4 seconds mean? Does it need to be tightened or can it mean it is going bad?

By any chance is the squeel coincident with anything else, like an accessory clutch cycling on and off?

A squealing belt can mean one of several things:

- The belt is going bad and needs to be replaced.

- The belt needs to be tightened.

- The belt tensioner is faulty and needs to be replaced.

- One of the components that is connected to the belt (alternator, power steering pump, air conditioner compressor, whatnot) is seizing up.

It could also be any combination of the above. Any neighborhood mechanic should be able to handle this.





(I listen to a lot of CarTalk)

Also note that tightening might fix it but you must make sure you tension it properly. If you overtighten you risk stuffing the bearings in the alternator and whatever else runs off that belt (water pump, PS, AC compressor etc)

Over time the belts do stretch slightly but they also go hard and shiny. Generally I'd say just replace the belt unless you have good reason not to.

How do you know for sure it's the alternator belt. Some cars have 2 or 3 or even 4 belts for all the accesories. Newer cars tend to have serpentine belt arrangements where basically everything runs off one big belt snaking it's way around.

And, trust me, you should get this looked at during your earliest opportunity. You do not want to have that belt break at some random moment. Random, of course, in the Murphey's Law sense of it being a cold, rainy night with lots of wind, you are in a hurry and suddenly need to arrange for a rental and a tow with only $20 in your wallet...

Do you have air conditioning? If so, it's probably the clutch or clutch bearings on the AC compressor failing. It may be the belt for the compressor slipping, but the bearings are more likely.

pca

take a look at this:
http://got.net/~danj/fiat/pulley.jpg (this part is off a saab, not a fiat)

sometimes the pulley that drives the belt fails and makes the same sound you describe.

what kind of car is it? (year, model, engine)
if the car uses the 'serpentine' style belt (kinda flat) you may also want to check the idler wheels/bearings that tension or re-direct it.

don't ignore this problem. something as simple as a bad belt will bring me a head gasket job at least once or twice a month.