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
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