Automotive → [Help] Serpentine problems/questions

2001 Mercury Sable LS Premium, 3.0L

Previous known history - old owner had problems with this belt as well. Constant whining mechanics couldn't fix. Was replaced just once though.

I replaced the belt about thirteen months ago when I bought the car (and the whining stopped). Drove for seven months, sat for about five months being started intermittantly. Getting it back on the road now. Driving today and after about 30 minutes there was a sudden loud 'thwapping' sound (thought I'd got a stick in a wheel). Pulled over and diagnosed a thin (1/16th inch cord) strip of the belt had peeled off. Removed that, quiet. Ten minutes later another piece started thwapping. It's now narrower by 1/16" all the way around and one side is all wavy so it ripped off and wasn't cut.

Got the car home but very curious why a thirteen month old belt would start peeling like this? Faulty belt? Dry rot from sitting? Why is it only this belt?

How is the idler pulley, (bearing freezing up or play) and or the bracket that holds the idler (spring tensioner).

Are all the pulleys in align with each other, sometimes work has been done (ie water pump) and things don't get put back properly.

Maybe something else is failing (AC, Water Pump, Alternator, and etc) that the belt rides on.

To start with, I would say the belt has to come off and you will have to inspect each pulley for play, rough turning, and visual of the grooves on the pulley make sure nothing is stuck in one of them.

Alignment of all the pulleys has to be in the same plane, just one of them slightly out of line can destroy belts.
Tensioners and idler pulleys have to be in good condition.
I use OEM belts, I had some issues with third party belts.

I lost a belt in Williston Fla. Put in a cheap replacement, A year later driving through same town, the belt went again. Got a name-brand belt and it seems better but power-steering slips when cold.

The cheaper ones from auto parts stores are crap.

This^^^^

I bet one pulley is slightly misaligned and that puts extra pressure on one side of the belt.

You may be able to diagnose which one by looking at all pulleys one by one while the engine is running.

If it's not getting worse quickly and the belt replacement is not too difficult (meaning you can do it on the side of the road ) you can just carry an extra belt all the time and the tools needed to replace it. (On my car I can do it in ~5 minutes and I only need a 15 mm wrench and and a belt)

I have also seen belts put on one groove off on one pulley. That will cut the outer edge off.

Many front wheel drive cars it is not easy to replace. Last one I did, you had to remove the engine mount to replace the belt.

Yeah, not only is this front wheel drive but it's a FORD so it's back to the mechanic on Monday.

How many miles are on it?

About 91,000

As others have stated possibly a alignment problem. But also as pulleys wear the grooves can become sharp and cut the belts also. Just a FYI.

another thing to look into is how many grooves are in each pulley. I have seen alternators replaced that have one less grove than the rest of the system.That will also chew up one edge of the belt.

Well, removing an engine mount may make it a slightly non-trivial job....

Interestingly, I have replaced my serpentine belt 3 times because in 2 cases it was squeling so loud that I couldn't tolerate it, but I could never see anything physically wrong with the belt. I keep one of old belts in my car, just in case. I usually drive a RWD vehicle, so a belt change in my case is a piece of cake.

NM

Found the problem - the a/c compressor pulley is out of alignment by about 3/4".

WTH happened there? How did it get that far out?

This is the replacement belt that was installed yesterday.

I looked at rockauto and it looks like the wrong pulley was put on it.

Sorry to hear it. Too bad this can't be remediated by the bozos that installed it. For free!

I'd be in someone's face over this.

Working on figuring out which shop did it but it's out of warranty anyway.

I think I'd try anyway. Nothing to lose, right?

It must be cheaper to just replace the pulley. Replacing the compressor will require evacuating and recharging the system.

said by Juggernaut:

---

I think I'd try anyway. Nothing to lose, right?

---

Of course I'm trying anyway

Most pulleys fail due to compressor failure.

The compressor will likely have to be removed to remove/install the pulley.

On the top rockauto pulley picture, the flat part (lh side of pic) faces the frame rail. The pulley in the picture does not appear to be the same as the one on your vehicle.

Wow, I didn't think it would be such a subtle issue....

The original mechanic will be replacing it for $300 total, saving $400 over the mechanic who diagnosed it. I'm happy with the price.

Nice! Glad to hear it's getting sorted.

Well, $300 and some homemade brownies

Bribes can work well!

Once the correct pulley is installed I would get a GoodYear GatorBack belt for it.