So when I first got the car, alternator in it had a bad voltage regulator. It seemed to run alright otherwise, no squeeling or obvious slippage. I replaced it with a napa reman unit which had a slightly different pulley on it, it is larger, but the notch was about the same. I've now gone through two belts, both of which I've had tightened just right and they ran fine for about two trips, then started slipping and broke.

Now that I look at it, the belt was running fine from the alternator back down to the eccentric pulley, but was wobbling from the water pump to the alternator. It looks like the water pump pulley is misaligned with the eccentric and air pump by a reasonable amount.

Would this cause the belt to snap? Or is it cheap belts/wrong alternator from napa?

I've searched around, and found people had some success in adding spacers to the water pump pulley, but I'm honestly not too sure how to take it off and the FSM doesn't seem to say other than when rebuilding the engine.

[EDIT] Whoops, totally forgot to add it's a 1990 GXL coupe.

 

I might be talking out of my *** here but if my memory doesnt fail me the S4 alternator goes behind the alternator bracket and the S5 goes on front or viceversa and if you put it on the wrong side it will end up causing this. but yeah I have heard about other people running into the same problem. what you can do is try both behind and in front of the alternator mounting bracket to see which one fixes your problem. I'm sure if you search arround here in the forum you will see what I'm talking about.

Good Luck

 

Everything I've found so far says this is only an S4 issue, and the S5 doesn't have that problem. Also, this alt is only going to fit one way.

 

sorry dude dont know what else to tell you right now. have you previously messed with the waterpump? is the waterpump spinning freely? did you compare the alternators to make sure they were the same? was this an issue before you changed the alternator? if you can post some detailed pics maybe that would make it easier to figure out whats wrong.

 

I haven't had the car for very long, but at first it was running fine without any slipping problems. The alternator I got it with had a bad voltage regulator, so it was running about 16V. Replaced the alternator and I've been having problems with the belt since.

The previous owner did have an issue where the dealer (she always had repairs from the dealer) had replaced the belts and she left the car in the garage for several months. Next time she went to start it one of the pulleys had been bent, which they then replaced. But she didn't know which part it was and couldn't find the invoice from the dealer for it. So it is very possible it's a pulley issue.

The first belt (napa) I'm relatively sure I overtightened. The second belt (dayco top cog) I just slapped on without cleaning the crud from the first from the pulleys, so that might've been the problem to begin with. I'm going to try and put belt three (dayco top cog #2 hurrah for warranties) on now after cleaning the pulleys up and applying some belt dressing to see if it works alright.

I do very much appreciate the help though.

 

This is part of your problem, all pulleys should be aligned. The alt. belt should ride in the grooves of the pulleys closest to the engine.

Also, check the pulley on the reman alt, i seen alot of them with the wrong pulley on it. I worked at advance auto parts for years, and had to swap the pulleys back on alot of them.

 

Problem is I can't really tell if it's off, or if they are misaligned by how much.

Would it be possible to buy just a pulley and swap it on to the alternator? I should've kept my core until i could swap them, but it's long gone now. With this much aggravation I'm considering going to Mazda and plunking down the $200 for a dealer part.

 

yes you can replace the pulley on the alternator. last time i did it i used a Impact gun and was fairly easy.

good luck

 

OEM belts are the best.

 

Cleaning up the pulleys/ belt dressing seems to have done the trick for now. It sort of works, as in it begins to slip sometimes, but then will catch and work fine. I'm running it for now, but ordered a new ebay alternator that at least has the correct pulley. I figure I'll run that and if it works I'll have a spare and swap the pulleys if need be.

 

I am just wondering WHERE you put the Washer/Spacer on the Alternator When installing it?It should be at the Back of the alternator.If it is at the Front,then that would make the Belts misaligned..S4,by the way.

 

Engine is an S5.

 

So while it appeared to be working fine, the belt decided to start slipping and snap on me on my way out to see some fireworks.

The belt was severely worn on one side and the other was fine, so it's definitely a pulley alignment issue. I've ordered a new one off of ebay to see if that fixes things. Is there any way to check for sure that the pulleys are off? or is it a "just eyeball it" thing?