redwake9112

Aight...at high rpm's....when accelerating or running down the freeway for about 30 minutes at seventy...my belt begins to shriek bloody murder.....the noise is horrific. It will not make a sound until I have run the truck for several hours, and then I will accelerate pretty hard and the belt starts screaming...and it stops after about 45 minutes of this....then returns 30 minutes later.....WHAT IS WRONG??!! New water pump...compressor is out of commission..all else is good.redwake

Clunk

Next time it acts up, pull the belt off, check the pulleys that are driven and see what's hard to turn.

loch

good advice and dont forget check the idler, somethings freezing up.

Bill Tomlinson

Mine acted similarily for a long time. I did notice some jumping in the idler.... it was not the problem. The problem was a failed bearing in the alternator which allowed the pulley to rub on the alternator housing.. sometimes. The sound would come and go. Eventually the alternator seized, the belt broke and I found out that it is possible to drive a Cummins about 20 miles in 90 degree weather without a water-pump on anything. I drove slowly and shut down three times when the temp got above the normal range. No harm was done. One of the peculiar things that was happening before the final failure was that the belt wore one edge very fast. I picked up a used alternator in Phoenix for 90 bucks, threw on my old belt and was good for the return trip to the great white north.

By the way, when everything is in good condition, the belt does not jump around at all. It almost looks like it is not moving. Any jumping around tells you something is wrong.

jrussell

Is this sound happening only when your fan clutch engages? Maybe a bad clutch, bad bearing, or just a loose belt? It would make sense that a slightly loose belt might only slip when the fan clutch engages on the highway at high RPM's.

Bill Tomlinson

In my experience, these belts don't slip unless something is seized. They then fail really fast. Some folks carry a non-AC'd belt incase their AC pump seizes out in the Boonies.

loch

I have never seen but one slip, and the idler spring was broke, i agree if its slipping something is siezed

fire1861

What is the Napa part # for a non-ac belt? That would prbably be a good idea.

Bill Tomlinson

Off hand, I don't know what the part number is but the supplier should have a listing. I believe you can find it if you do a search on this site.

On the original posting that started this thread, I am a little curious now about what Redwake meant about "out of commision". The belt is dependant upon the bearings on the compressor. It does not matter if the clutch is engaged or not. This can cause a problem. Another good reason to carry a non AC'd belt. By the way, you can use a compressor from any old mopar of the same vintage but you have to grind one aluminum flange down a bit to get a fit. Be careful with the line connections. If you need to switch to R 134a change the oil ... pag oil... is used here. It is spendy up north here but cheap in the Excited States Of America. You CAN refill with a little propane instead of freon just use about 1/3 as much. Don't go by the sight glass just the pressure on the fill guage that comes with the cheap kit- if you do not let the pressure get over the green mark you are safe. I added a fan to cool the condensor. It operates when the AC is on only.

It is a no-brainer to cut a propane line from an old appliance and connect it to the fill kit.

Experience with selecting these old pumps has taught me to look for one where the freon lines come off the pump at the same weird angle as our old trucks.

flashgordon

I agree with "some thing is starting to siezed" or trying to, but before you go down that road or when it's makeing noise, and you have the belt off. Check for any kind of oil or anti-freeze that may be on the belt an pulleys

Clean the pulley with brakes cleaner and the belt with HOT soapy water!
don't us brake cleaner on the belt cus it don't work near as well as soapy water.

edwinsmith

I wonder if the compressor is seized and the A/C clutch is somehow being engaged. That would raise a heckofa racket for sure. If the tensioner is on the weak side and the fan clutch engages it could be the belt slipping. I've seen them slip when the thermostat opens which makes the WP work harder.

Edwin

Boatnik

IF anything causes the belt to slip for that length of time, I would think there would be one heck of a smoke screen out from under the hood.

redwake9112

Hey ya'll...my computer has been acting up a bit...so I haven't been on much...aight....what I meant about the compressor is that is stopped working about three weeks ago....no a/c. The guy i bought it from said that from time to time the belt would squeak even when the a/c worked. I have not replaced the a/c yet, but I don't know if that is the problem....the belt squeaks, well, usually, only after the truck has run for some time at highway speeds or if I am driving with a heavy foot. Sometimes the belt squeaks in the morning, just a tad. The belt squeaked like crazy awhile back when the truck was leaking coolant and the water pump was on its way to Hades. I replaced the w/pump but the squeaking has not stopped.

The belt only squeaks when my foot is on the accelerator, if I take it off no squeak....again only at higher rpms...like 2000-2500 during acceleration....just top end. Also....it will squeak at highway speeds only for a while and then it stops.......perhaps it is a cheap belt? or fan clutch....lol.....no clue...I am having a guy look at it monday. I do want y'all to know that your opinions and help have been awesome...I appreciate it....love this freakin' site. I will be back with more questions. redwake

charliex25

Flash :
I had an experence that got tranny oil on the belt. The tranny line cooler line came loose and got all over the belt. I got the line fixed and headed to the nearest car wash. I put engine cleaner on the belt and it cleaned it right up.

Charliex25

flashgordon

My favorite fix if the belt is suspected of having oil or anti-frezze, is floor dry.......yess floor dry. it makes a ho lot of a mess, but if the contaminent have been stoped the this will dry the belt and pulley up nicely and the noise belt should go a way.

I would still pull the belt off first (when it's hot) and see if one of the accessory pulley is getting tight,ac bearing included!

Charliex25 for a bad oil leak or a slow, but long time leak that would be the best way to go!!!!!