2 perplexing, 1 tech auto Q's

[markkw]

Okay, for all y'all car junkies..... both of these are on my '92 dodge caravan 3.3L V6 automatic & a/c.

1- When it rains the serpentine belt comes off. Idler & tensioner are good, all sheaves in proper alignment. Splash shields are in place on the bottom. I'm thinking it's got to be water coming in the bottom somewhere, somehow that I can't duplicate the gripe with a garden hose. Only happens when there's standing water on the road. I thought it was related to increased belt loading of the a/c compressor cycling when in defrost but I pulled the plugs off it and still have the same gripe! Friggin dodge!

2- Same van, but the windshield is out of the wrecked grand caravan. I have scrubbed the inside of the windshield with everything I could think of including a combination of window cleaner & Comet cleanser. I still get fogging/steaking on the inside when the air is damp. Running defrost on high fan & heat keeps it down a little but it's still an issue especially when you live where it's hot & humid or cool & damp all the time. Any ideas on this one?

3- The tech Q ... Does anyone know what 8-lug standard steel 17" rims will fit on my 8-lug 3/4 ton 1985 Chevy pick-up? Currently it's running 16" and I came across a bunch of used 17" tires for the right price ... now I need 17" rims ...

[garystewart]

I use Rain-X on my Model A windshield, no need for wipers. They make both inside and outside stuff. Works great

[alany]

1) Check the harmonic balancer. Even if wet, the belt shouldn't come off. The balancer may be loose or the rubber bonding it together might be deteriorating causing a wobble. Even though it looks like the pulleys all line up okay, at speed it might not.

2) Gary's answer is good. I only wanted to say that if you ever want to use cleanser on your windshield for any reason, use Bon Ami (if you can find it). Unlike Comet and other "regular" cleansers, it is non-abrasive to glass.

[nutrivet]

Sometimes when a ribbed serpentine comes off due to a tensioner or alignment pulling it a certain way, the bands of the side have stretched. So that even when it's aligned later the belt really wants to go off that way;
It has to be bias the other or replaced.
The windshield thing could be the bond,air bond was disturbed in the laminate between the inner/outer glass. So then there are two sides of glass within one and a slight difference in moisture.

[gregd]

I don`t know who told you Bon-Ami cleanser isn`t abrasive. They lied. Caterpiller used to list a break in compound YEARS ago if you rebuilt an engine and the rings wouldn`t seat, you would put some of this in the intake as it was running. If you ordered that part number, care to guess what you got from Cat?
If your guess was a can of Bon-Ami cleanser, you win.

[markkw]

Got ... maybe ... we'll find out next time it rains and I have to go somewhere. I didn't catch it till this morning when I went to check the oil, I saw the tension pully cocked to the outside. I cycled the tensioner a few times and it came back to running the pulley true but a few more cycles and it went back to leaning. I saw it was off in the spring pivot, spare one had too much play in the pulley bearing so I used the existing pulled on the other spring unit, so far seems to work right.

On the windshield, it's something on the inside surface of the glass itself. I thought it was just cigar smoke from the previous owner but that should have come off with the multitude of cleaning agents. I'm going to try acetone next.

[tech4]

It seems that there are two different Bon Ami cleaners www.unofficialbmw.com/all/carcare/all_use_bon_ami_on_windshield.html

I remember borrowing my aunt's 1949 Ford when I was a teenager and the rubber came off the windshield wiper and scratched the glass. I spent hours scrubbing with my mother's Bon Ami and completely removed the scratch.

[alany]

@greg. I said non-abrasive for glass. I wouldn't put it my crankcase or stick it my eyes!

Edit: Thanks to tech4 for the additional info.

[sselander]

they make an idler pulley with grooves in it that should hold the belt

go to rockauto.com and lookup belt drive idler pulley

[sselander]

They had a TSB on this, I found a writeup on how to fix it:

www.alldata.com/service_provider/techrx/2001/20010615.html

"Snow or rain can enter the engine compartment from underneath the vehicle and force the serpentine belt off of the idler pulley.

But what is the root cause of this problem? An incorrect idler pulley bracket is causing a slight misalignment of the serpentine belt"

[markkw]

Sven,

That's the condition I had but it was intermittent - something that I didn't see for a long time. The bearing itself was fine, the problem was in the mount pivot point in that as the normal cycle of tighter-looser went about, depending on where the pivot stopped, it was either in proper alignment or not. Using the wrench to cycle the tension pivot, I had to move it several times before it stopped at the point where it left the idler sheave leaning to the outside and thus where it could run the belt off. I haven't hit any rain yet but I'll keep y'all posted on if this fixed it or not ... I don't mind putting the belt back on but the last time it happened I was in a swamp area and the mosquitos were thicker than a love bug swarm!

This idler runs on the back of the belt, I did note that some chevy engines use an idler sheave with sideboards so the belt can only run to the stop unless it's real bad out of alignment to where it could climb over the sideboard.

[markkw]

FYI on the cleanser ring-seat trick, my first choice is Dutch Maid brand, worked like a charm. If you want to keep from plugging up carb/t-body ports, pull the plugs and put it directly into the cylinders with a duster pump/bulb. If doing a diesel, direct-injected or where access to the plugs is a problem, a 50/50 blend of cerium & talcum powder (must be thoroughly tumble-blended) can be injected through the intake. Be sure to change the oil as soon as the seating operation is done or you'll be ripping the whole thing down in short order.