Going through a belt every month? Check your harmonic balancer.

Dear Car Talk

Dear Car Talk | Mar 01, 2000

Dear Tom and Ray:

My daughter's '92 Ford Tempo, a four-cylinder with the usual peeling paint,
is shredding serpentine belts. I have installed four new belts in the past
six months. After installation, the belt immediately begins to wander off
the water-pump pulley. At more than $25 each, this is getting ridiculous.
The last time, I had to drive 120 miles to rescue her. Someone suggested
the harmonic balancer may be bad. What the heck is a harmonic balancer, and
what does it do? -- Rich

TOM: I don't know what a harmonic balancer does, but she charged me $80 an
hour and my back still hurts.

RAY: I think the problem IS your harmonic balancer, Rich. The harmonic
balancer is the pulley on the front of the crankshaft that provides the
power to run the belt. It's made up of three pieces. There's the steel
inner part, which bolts to the crankshaft; there's a rubber sleeve around
that which dampens crankshaft vibrations; and then there's the outer steel
part, which has grooves for the belt.

TOM: And what happens is that the rubber sleeve wears out and pushes the
outer part of the pulley away from the engine. That pulls the belt off of
the other accessories, including the water pump, which is what ultimately
shreds it.

RAY: What you need to do is see if the pulleys are in alignment. Using a
piece of string, or a straight edge, look down from the top and see if any
of the pulleys are not in the same plane. It could be any pulley, but it's
most likely to be the harmonic balancer.

TOM: Unfortunately, it's not a job you want to do yourself. Ford engineers,
in their wisdom, put the engine about an inch away from the car's frame.
And the harmonic balancer is 2-inches deep. So you have to disconnect the
motor mounts and move the engine in order to change it.

RAY: It'll cost you a couple of hundred bucks to have someone else do it
for you, but it's one of those jobs where it's well worth it. Unless you
don't really need your knuckles. Good luck, Rich.

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