Ocassionaly when driving in powdery snow my alternator belt will silp and squeal and the alternator quits working for 15 - 30 sec. Only does this with snow, rain doesn't seem to bother.

Pulleys are clean and properly aligned, new belt installed and tensioned properly.
Still slips.

The truck is a '97 f-250 7.5l.

Any ideas or suggestions?

Thanks.

 

It either has to be a bearing on one of the pulleys going out, The tensionor binding or not holding tension, Or possible a cheap belt.
Why only in the snow is the $60,000 question. Unless you have a couple of sno packing mice shoving it on the belt when it snows. Ha Ha.
After I wrote this I thought the alt bearing going out with snow the temps are lower than rain.
Craig

 

It's a napa belt. There is no tensioner goes around water pump, air pump and alt. tension set by moving alternaror. The bearing on the alternator appears to be fine.

Normal driving evrey thing works fine. Just wondering why the little bit of moisture from the snow is makes the belt slip enough to have alternator quit working.

I think I will put a new alt on and see if it is any better. As far as I know the one on there is original and may be getting a little tired.

 

Sometimes if a belt has been slipping enough it will leave a glaze on the pulleys. I suggest you try cleaning them off with brake cleaner then scrub them with a wire brush and/or medium sandpaper. Sad to say, you may once again need a new belt after all of this.

My Ford manual shows this for belt tension on your 7.5L equipped truck:

New Belt tension: 180-200 lbs.
Used Belt tension: 110-130 lbs. Used is defined as running for 5 minutes or more.

In either situation the tension should remain above 105 lbs. after 5 minutes of operation time.

 

There are 2 belts on it. One serpentine belt that goes around the crank, water pump, PS pump, AC, and a tensioner. The 2nd. belt goes around the crank, water pump, air pump, and alternator. This belt is adjusted by pivoting the alternator, like old-school V-belts.
Mine would slip too, until I adjusted it pretty tight...

 

There are two old timers tricks for curing slipping belts.They may work for you and will probably be only temporary fixes.
One is VERY CAREFULLY take a bar of hand soap and let the sides of the belt rub on it with the vehicle rub on it,or you can wet a clean rag with brake fluid and wipe it around on the sides of the belt with the vehicle off,on old beaters we'd do it with the engine running but it can and will sling brake fluid all over and brake fluid is nasty stuff,it will remove paint and you don't want any flying on your face or anywhere near your eyes.

 

That works pretty well on V-belts, but this has micro-groove serpentine style belts. I don't see why it wouldn't work if you get it on the ribbed side of the belt... It's the only vehicle I've seen with a micor-groove belt that adjusts manually...

 

I ran into a manual tensioner on my old jeep cherokee. My manual called for a "belt tensioner gauge" and damned if I could find one anywhere.

So what I ended up doing is measuring the play on the s-belt on my pick up and using that as a guide for the tension on my jeep. I don't know to this day if I ever got it adjusted correctly, but I never had a problem with it, either.

 

My fault,I was thinking the alternator belt was a v belt.But,I can't see why either trick wouldn't work on the inside (drive surface) of a serpentine belt.
There are also a couple three other good uses for brake fluid on a vehicle,but I'll save them for a different thread.
As far as setting tension on a serpentine belt a rough rule of thumb is to grab the belt between your thumb and finger (with the engine not running) between the two furthest apart pulleys and see if you can just turn it 90 degrees,if not it's too tight.Too tight is worse than a little bit loose in belts,too tight will eat bearings,loose will slip some.

 

If anything the belt is too tight rather than too loose. Winter is almost over so I think I will just live with it and replace the alternator next fall.

Thanks for the help!

 

Is the second belt a V-Belt or Serpentine?
Craig

 

The second is also a micro-groove serpentine belt.

 

THANKS FOR THE INFO
CRAIG