What Causes a Car to Squeal?

When a car is squealing the most likely culprit is your belt system.

Most vehicles have a serpentine belt system, which is a single continuous belt that "snakes" around the

pulleys of the multiple peripherals on the front of an engine. Systems such as the alternator, the power

steering pump, water pump, or the A/C compressor are all interconnected by this single belt. Vehicles

manufactured prior to the late 1980's may not have a serpentine belt, but instead may have multiple V-belts

for each of the different systems requiring them.

A belt can squeal for many reasons but the most common three are:

There may be fluid on the belt The belt may be too loose The belt may be too tight

To find out which of these is causing the squealing first open your hood and find your belt. It should be

quite apparent, as it looks like a big black rubber band snaking around the front of your engine. Now rub the

belt with a rag, if the rag soaks up fluid than that is most likely the cause of the squealing. Fluid on your

belt can be caused by one of two things, one is that dsomething may have recently leaked on your belts. For

example you may have spilt oil while adding to your reservoir. If this is the case you should use a low

pressure hose to wash your belt, ensuring that the runoff is properly cleaned and disposed of. Next wipe your

belt dry with a clean rag. Finally, allow the motor to idle for a few minutes to dry any water and then drive

your car, if the squealing stops then that should be the end of the your problem.

However, if the squealing stops, then starts again soon, the residue on your belt may be indicative of a fluid

leak in one of your peripherals. Have a mechanic check that pressure is maintained in all hoses, and check the

fluid levels in all systems, such as power steering, oil, and the radiator.

If there is no fluid on your belts, your belt may be either too tight, or too loose. A quick way to check if a

belt is too loose is while the motor is running, pour water over the squealing belt, if the squealing stops

than your belt needs tightening. You can look for the belt tensioner which should look like a wheel connected

to an arm, about half-way down the front of the the engine. The location of this tensioner obviously varies

between car models, so you may need to consult your owners manual. The ideal tension on the belt is around 3/4

of an inch play evenly throughout, any less or more than this can cause squealing, and reduce the lifespan of

your belt.

If these three options fail, an alternative may be belt dressing compound which should be obtainable at any

automotive shop. To apply, while the engine is running, carefully hold the stick against the moving belt. One

should bear in mind however that while this compound may silence the squealing, it is only a temporary

solution, and will only quiet the symptom, not fix the problem.

If all options are employed against the belt with no results. The problem may be found elsewhere in the

vehicle. You should check the power steering fluid reservoir, the wheel bearings, the water pump, or the

brakes. If the problem is not encountered however, the vehicle should be taken to an auto mechanic for further

examination.