Serpentine belt Idler pulley failure
 

Hi all,

Here's a warning from our experience.
On a 2004 '3' with the 2.3 engine, at 6300
miles, the serpentine belt idler pulley
near the top of the engine failed. Now the car
is sitting at a Maz dealer waiting for a repair part
which is now on 'national backorder'! Not good.

There was a fairly slight ticking sound coming
from the engine compartment for some time.
On a road trip, it got somewhat louder. With an open
hood and the engine running, I could see
that the pulley was not round and that the belt
was bumping over it somewhat. Upon stopping
the engine, I could see a single crack extending
from the edge in toward the center. It
wasn't going to make it much longer. It did
about another 30 miles before total failure. Then
a big pie piece of the pulley broke away, the belt loosened,
then no battery charging and quick overheating
ensued.

It's dumb that that they insist on replacing the whole
tensioner assembly. Simply replacing the pulley/bearing
is all that is needed. We had a very similar failure
on a very similar part on a 1996 SAAB 900. I think
the two parts are almost identical, but can't verify
it. I'll bet there are similar enough parts on other
cars that you might rig at least a short term fix with
a 'foreign' part .

If you hear a new slight slapping/ticking sound
coming from the engine compartment, check it
out. If yours is failing go straightaway to the
dealer if you can and get it fixed (if they have parts 8-< ) .

Torp.

wow, something to keep an eye out for certainly.

If it's any consolation my mazdaspeed protege slightly overheated and blew a headgasket at 3200miles. When it blew the headgasket I was under full boost so the motor hydrolocked on coolant and slung 2 rods. Dealer basically said I was driving it hard and that isn't covered under warranty. It looks as though your dealer is going to replace it for free.

so if we have a mazdaspeed, we have to drive it without hitting full boost, cuz of the fear that if u hit full boost, the dealer will say u were driving it hard, and wont fix anything that went wrong under warranty, thats stupid if u ask me

and dunt they always go on about how they can get to full boost so early, some dealers are whacked (lol new word i started saying)

anyway thx for the heads up torpedo, definately cool of u to do this.....
i geuss mazda should do some redesigning of the part, make it stronger, faster, better than it ever was.... lol

thanks for the info torpedo....

I just looked at my 07 with 13k miles on it and after pulling the belt I noticed the idler pulley was sloppy, sideways axial tilting sloppy. This should never be so loose, otherwise things looked ok. This may have been a bad lot of bearings in the middle of the pulley - not sure how yours got cracked. I'm going to ask for a replacement when I go in for my yearly inspection this month. And the workshop manual doesn't look to have any specs for it, though I measured about 0.025" play in the thing which is very noticable.

Torpedo is right. I just had to have mine fixed. I thought at first that it sounded like a misfire in the spark plugs. Turns out the alternator was working over time charging a dead battery causing tension on the belt assembly destroying the pulley. (obviously they're pretty cheap pulleys.)

Definitely keep an ear out for that sound and check it out.