Mazda squealy belt saga....

Mazda squealy belt saga....

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interloper

Original Poster:

2,747 posts

262 months

Saturday 16th February 2013
quotequote all
I run a little MX3 as a daily, recently the belts started to squeal, so as a precaution I bought a new alternator and PAS belt, with the intention of changing them over a weekend.... On the journey home the alternator belt snapped!

Anyway, I faffed about changed the belts, took the car for a test run, the squeal returned then the belt shredded itself, oops. The next day I had a grope around the pulleys, there are only two pulleys other than the crank. The water pump pulley felt fine, the alternator's pulley felt heavy. So I then changed the alternator figuring that it was duff and also the squeal got worse the more strain you put on the alternator, seemed like a smoking gun to me.

Well I finally fitted the new alternator, checked the belts set the tensions and guess what, the squeal is back, loud as ever. I had a quick check around the alternator pulley feels hot and so does the water pump's. I'm a bit puzzled and pee'ed off, suggestions please!!!

ch427

9,742 posts

240 months

Saturday 16th February 2013
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what sort of condition is the battery in?
only thing i can think of is a big demand on the alternator causing the belt to slip

Mikey G

4,784 posts

247 months

Saturday 16th February 2013
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Worn crank damper pulley can also cause squeal. Friction between the inner pulley and the outer can also cause heat quite quickly.

interloper

Original Poster:

2,747 posts

262 months

Sunday 17th February 2013
quotequote all
Thanks for your input guys. I think I may have solved it, initially when I just replaced the belt it was done back up pretty tight, I half suspected it was too tight and maybe the alternator wasn't to blame, for it snapping. Setting everything up with the new alternator I had them slightly loose.

This morning I charged the battery up off the other car and played with the amount of slack, its now about as tight as when the new belt failed (when fitted to the old alternator) and it runs fine, which is good because it rather vindicates me buying a new alternator!

Unfortunately I cant road test it properly as the MOT ran out whilst its been off the road, so its first proper test will be tomorrow morning on route to the test centre, fingers crossed....