I have a 1990 Oskosh Chassis in my Motorhome and it has a 460 EFI engine. Since replacing the engine three years ago, I have had nothing but problems with the cooling system ... primarily the serpentine belts. I can't keep them on. I go through belts like I change underware.

Recently I had the A.I.R. pump freeze up and take out a belt, about 500 miles from the house and no one could locate another pump. So we removed the A.I.R. pump and used a shorter belt. Now, the belt wants to squeal unless I squirt a little water on it and then it quiets down until it drys. I have tried several belt dressings and it makes the squealing worse.

While I was working on the engine to get the right size belt, I niticed that the upper hose is now collapsing. At the time of the Long block swap, I changed out the H2O pump, thermostat, installed a rebuilt radiator, with all new belts and hoses. In otherwise ... everything in the cooling system was new 3 years ago and less than 7,000 miles ago.

I also get some weird temperature readings on a mechanical gauge. It seems to take forever to get up to temperature, and with a 180 "T"stat it will runs about 215*, but no boil over. I changed the "T"stat to a 195* and I still run the same temps.

I am starting to wonder if the wrong water pump was installed (the opposite rotation on a "V" belt).
Is this possible that the wrong water pump would give me these type of problems?
Without taking off the pump, is there a way to tell the difference between a pump for "V" belts as opposed to a pump for Serpentine belts?

I am getting tired of throwing belts and working on the cooling system.

 

You are throwing belts because at least one of the pulleys is misaligned. Find which one, realign it and problem solved.

 

I forgot to add, I have checked all pulleys with a straight edge and all pulleys are in line with each other. But thanks for the thought.

 

There are only three ways for a serpentine belt to come off;

1. Pulley misalignment.

2. Belt installed wrong, not aligned in all the pulleys correctly.

3. Tensioner bad.

If one of the accessories had had bearings will do it but that comes under the misalignment part.

 

OK, I think that I found that the belt was just a bit long. I was finally able to take a proper tension reading by removing the fan shroud and found that the belts that were installed when the belt was replaced, the last time, was a bit long. The tensioner was almost at the far end of its travel. So after two days of trying different sized belts, I finally obtained the proper tension and the tensioner aligns in the marks (which I can now see).

I used a NAPA 25-060760 Belt that runs around the Crank, W-P/Fan, Tensioner, a Hyd Pump and the Alternator. I also checked to see if there was any excessive end play in any of these pulleys. I even replaced the tensioner ... once again, NAPA replaced it just in case the tension was not proper.

So then I was faced with a squealing belt. So off came the belts again (for the umpteenth time) and I cleaned all the pulleys and tensioners, both chemically and with a wire brush to rough up the surfaces. I went out and got a new belt of the right size and still I have a squealing problem.

If I squirt the troublesome belt with water, it will stop squealing, with water but as soon as it dries the squealing comes back. Yesterday I did get to drive in the rain and the squealing went away. BTW, the last time I drove in the rain, the squealling went away and that is what prompted me to use water to try to stop the noise.

This thing is driving me out of my mind ... what little I have left. ANY help will be appreciated.