belt slip in snowy conditions
 

This is a consistent, repeatable, and predictable problem.


When driving in snowy conditions where there is a ton of snow in the air, either from driving wind or a passing truck on a snow covered road, the belt will slip to the point where the alternator is no longer working.


the belt is only a year old (20k miles), and I've replaced all three idlers (they were bad, nothing related to this).


the tensioner feels very tight.


any ideas on how to keep this from happening? it's a little worrisome driving home in a blizzard and knowing the alternator isn't working and not knowing how long it will take to come out of it.


ideas?

Did you change the entire tensioner or just the pulley on it?

i did not change the tensioner or the tensioner pulley.

just the belt and 3 idlers (2 smooth and 1 ribbed) thus far.

the tensioner feels very tight and tensioner pulley turns smoothly so i hadn't really considered them for replacement up until it slipped in the blowing snow again this week.

worth throwing a tensioner on it?

That's what keeps the belt tight and since it seems to be slipping you either have a weak tensioner or the brand of belt you bought isn't good enough. Most prefer Gatorback brand of belts.

I'm curious - how could you tell the belt was slipping as opposed to the alternator going intermittent?

after a period of time, depending on engine speed, the belt will squeal for a second or two and then the voltage comes back up to where it should be. and the problem is more prominent when you've let off the gas and the engine speed goes down closer to idle. if you are in a driving snow, the voltage doesn't come back up when you step on the gas, then the belt will squeal and all is well again.

but, i've had it happen at highway speed too. i got passed by a semi on the interstate and it was a complete white-out until he got clear around. then i noticed the fan was blowing slower and the volt gauge was lower than it should be. then the belt squealed and everything went back to normal.

you are right though, until i heard the belt squeal, i thought the alternator just got "flooded" out and quit working.

i think i'm going to put a new tensioner on as a matter of maintenance. I noticed more pulley noise this morning as it was warming up. being that all the other idlers are new, the only one left is on the tensioner, so i think i'll just replace the whole works when it warms up a bit. I thought it was fine, but it's really hard to check them for sure by hand.

too cold to do much now. was -4°F this morning, and supposed to be -14°F tomorrow morning.... it can wait :)

Ah ha! I musta missed the fact that it squeals. Does the alt turn freely -as if the bearings are good to go?

Sounds like the tensioner needs to be replaced, but...
I did have a couple issues with my Fusion lately that showed me the range of belt lengths for the same application.
I was going to replace my tensioner because it was rattling.
Turned out that it was at the end of it's travel and hitting cast in "stops".
Looked closer at the belts offered for the car and found an inch and a half difference.
There used to be "belt dressing" adhesive.
I had a can and was going to try and apply it while I was still diagnosing my issue.
The stuff was probably 15 years or more old.
It hit the trash, but back in the day it used to come in handy.
Good luck.

If the belt tension is iffy, the snow in the air is probably is putting water on the belt and giving it some lubrication and causing it to start slipping.

I have never run into it, but I have heard that a faulty diode pack can cause a high pitched squealing noise. Anyone ever experience that?

Only in a radio. :)

replaced the tensioner today.

what a PITA. I'm not sure what kind of wrench they figured on a guy using to change the left side bolt, but luckily i had one with enough bend and long enough to get in there. if a guy had a 1" extension, that'd be the best. a 3" is too long and so is a deep-well socket. but ... after an hour or so of cursing ... i got it.

the bearings in the tensioner pulley were shot as well, so now everything is nice and quiet up front.

the new tensioner doesn't "feel" any tighter than the old one, so we'll see if this helps or not. I'm wondering if the belt isn't on the long side of the tolerances. i think the tensioner is most of the way toward the bottom of it's travel with the belt on it, so that might play into it as well.

if this doesn't work, i'll be looking for a serrated belt, hopefully one that's just a smidge shorter.

on a side note ... what the heck is it with the idler pulleys on the modular motors. every one i've ever had it seems like the bearings in the idlers don't last much more than about 100k before they are shot and squealing. but .. on the bright side, they are ALL new now, so hopefully i'll be good to 200k, at least in that regard.

I don't consider 100K on an idler bearing to be bad at all. It's not like it gets fresh oil on any regular basis. It gets greased once and then it goes through all sorts of heat, cold, rain, ice, snow, and other environmental conditions...all while turning at 1000s of RPMs the whole time.

On another note, you can press out and press in just the bearing instead of replacing the whole pulley. I buy them in a pack of 10 for 15 bucks or so. Now when I change one it only cost me around a 1.50 instead of 20.00.

In case anyone is interested, these are the ones I bought:
http://www.ebay.com/itm/131075163453?_trksid=p2055119.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AIT

I used a 10mm box wrench on the left bolt of the tensioner when I did mine and it came right out. Just had to break it loose with the box wrench and then it turned right out with fingertips. Took only a few minutes to remove it, change out the pulley for a new one and re-install it. If the bolt was crudded up it could take longer but there is plenty of room to work.


I don't pay $20 for my pullies either, I pay $7 a pop for Dormans on Rockauto and they work GREAT. Only thing that sucks is the ribbed idler is $17.99 but for a 100k item... eh...

well, ever since i replaced the tensioner the belt squeaks on a cold start.

drove in another snow storm last night and when i came to a stop the belt slipped when i went to take off.

next step is a serrated belt, i guess.

frustrating..... i replaced the belt because of this issue, and this belt only as 20,000 miles on it, and the problem has persisted despite everything being new.

i'm REALLY getting tired of working on this truck.