Alternator Belt Tension

Wiggybaby 67

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Protege5
The protege5 service manual says that when inspecting the belt tension it should be 88 lb-ft. It says when replacing the belt to set it between 110-150 lb-ft. I took off the belt to install a new one and don't understand the difference in the two settings. I also removed the AC belt and need to put it back on to the correct tension.
 
The protege5 service manual says that when inspecting the belt tension it should be 88 lb-ft. It says when replacing the belt to set it between 110-150 lb-ft. I took off the belt to install a new one and don't understand the difference in the two settings. I also removed the AC belt and need to put it back on to the correct tension.
A general rule of thumb is reach in and twist the belt....

If you can't stand it up sideways, it's too tight..

If you can turn it upside down,... It's too loose....

If you over tighten your belt, you'll wreck the bearing...

If it's under tightened she'll scream like a banshee...

Good luck with the balancing act...

I'm on my fourth alternator...


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Thanks, I tried that and think I have it right. Not squealing so must be tight enough. Can turn it sideways, so not too tight either. Not sure how many alternators came before this, it has 236,000 miles on it and I only account for 80,000 of those.
 
Three of my four alternators, had the bearing go out.

Before I started doing my own work on my car, I would take it in for service.... The mechanics just cranked the hell out of the belt.
It never squealed but the bearing would crap out in 6 months.

(a bad bearing sounds a lot like a belt squealing...)
 
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Three of my four alternators, had the bearing go out.

Before I started doing my own work on my car, I would take it in for service.... The mechanics just cranked the hell out of the belt.
It never squealed but the bearing would crap out in 6 months.

(a bad bearing sounds a lot like a belt squealing...)

This is exactly what I've been going through for the past year or so...my Mazda friend/mechanic changed the belt, it helped for a little bit...but, he told me the alternator was going out and that it was the bearing in the alternator failing...I just can't bring myself to buy a new alternator! But, the squealing is getting out of control and I can barely have the A/C on without it going nuts, and it's HOT here in Texas!

Any advice on a decent replacement? I really don't wanna drop $400...
 
I'm sure the Denso will be fine.

That's what I'm leaning towards...what do you think about the difficulty level of this repair? I've done LCAs, axles, oil, gear oil, rotor, brakes, calipers...I have a mechanic friend at Mazda that quoted me $80 for the repair, I believe. Not sure if it's worth the headache to save the $80...I'll do some digging on here about the repair.
 
The alternator unbolts quite easily.
The problem is that the alternator is trapped in the engine bay,... There's a few ways to deal with it.

https://www.mazdas247.com/forum/showthread.php?123748598-How-do-you-replace-the-alternator

Thanks for your reply, I read the post you linked earlier...I meant to come back and reply that I think I could handle the repair, so I went ahead and bought the DENSO reman! Wish me luck!!!

Oh, should I go ahead and replace belts at this time..? Depending on condition?
 
Thanks for your reply, I read the post you linked earlier...I meant to come back and reply that I think I could handle the repair, so I went ahead and bought the DENSO reman! Wish me luck!!!

Oh, should I go ahead and replace belts at this time..? Depending on condition?

I think it'd be silly not to.
 
I think it'd be silly not to.

That wouldn't be silly,... That'd be stupid...

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Or you could spend $20-$30 for a different brand... (a lot less in US dollars)

PS and by the way... A new belt is kinda fuzzy and grips the pulley better.

As little as a minute of squealing can "glaze" the belt and make it all slippery.

A new belt gets tightened up tighter because there is some stretch....

5 minutes running time makes it a used belt...
Run it five minutes and readjust.

(belt dressing or even hairspray can make a belt grip better and not squeal... better than a new alternator... )
 
Cool cool, I'll get some new belts on there...I'll run it for a few and re-adjust...do y'all use a belt tension gauge to measure tension, or just roll the belt over and judge by how far it moves..?

Also, any particularly great brands for belts in the US?
 
FINALLY got this repair done! I went with the DENSO reman alternator, two new belts, and all is right in the world! My P5 is running like a champ, and no more squeal!!!

THANKS Y'ALL!
 
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