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ac belt chatter

D

dtom2500

Tom
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Location
S. E. Michigan
Hey guys could use a little help. 1995 6.5 ac belt is driving me nuts? I replaced it last summer along with belt tentioner to try to elimanate the squeeling I get from time to time but could never get rid of it completly? I thought maybe I was getting high head pressure on hot days but the high side was reading in normal range along with low side around 45. The truck does run a little hot from time to time around 210 especialy when we get high humidity in the air but outher then that she runs around 190. Has anybody ever had any problems with pully/sheave issues? or maybe clutch fan?
 
Unless you got the belt tensioner from the dealer you got the newer belt tensioner assembly with the weaker spring. Several parts stores (like Cough! AutoZone Cough! Cough!) will do this to you.

The weaker spring can't take the load from the compressor and will unload and slip the belt. The newer trucks have the compressor on the driver's side so the tensioner, alternator bearings, etc don't see the AC load.

Your fan clutch is junk if it is over 5 years old. They loose 200 RPM per year due to age and wear. Have you cleaned out the radiators by removing the oil coolers and cleaning the mat of debris out from between them? Oil cooler to condenser is where the mat of derbis appears. High temps on the condensor can load up the compressor to slip the belt. A restricted orface tube can do the same. Idle and 2000 RPM tests will not show you road speed and pressures. Keep this in mind as you didn't say where and when the belt slips.

I assume it slips after start up or when the compressor kicks in like mine did with a new weak spring tensioner. Trip to the dealer parts counter and problem solved.

If you have removed the vac pump there is a different belt length and the belt will vibrate, flop, between the compressor and crankshaft. Normal. 454's had a idler pulley to stop this. 93's did not and vac pump engines used that to dampen it.
 
Hey makes sence to me, and yea I did get it from autozone last summer. As a matter of fact I was there two months ago questioning that belt tentioner and asked if it was sold with a new pully because, I couldent remember if I swapped the pully with the tentioner.. Anyways thanks for the info. Any idea where I could pick up a decent clutch for my fan? or maybe a step up complete without paying through the nose at the dealership? I know she can run a little cooler then 210.
 
Yea ive never delt with rockauto? seen there website but don't know anyone who's got anything from them. I did order a tentioner through gm this morning and that thing was hard to find. Gm discontinued it but I found a dealer in Altuna PA. that had one left @75.50 plus 12.00 for shipping, I guess thats not too bad all consitering factory replacement part. Ill just see if my belt chatter goes away and then do some research on hd clutch fans. I also plow snow in the winter here and this truck runs hot on the e-way unless I drop the plow down a couple inches off the road and I dont like driving like that "scrap scrap bounce bounce"
 
I order stuff from Rock Auto all the time. Do a google search for a current coupon code to get 5% discount.
 
Lots of info on here about cooling systems. There is a DIY fan clutch mod on here where you have the clutch turn on at a lower temp. One of the members with a plow had luck with the DIY thread. Myself I run the Kennedy Diesel low temp fan clutch, HO water pump and 180 T-Stat. This shifts the entire curve down for running hard. Factory T-Stats have some claiming better MPG over the lower ones.

I have already ruined a 6.5 over a cooling fan clutch so I am happy to get a brand new low temp KD clutch that likes to kick on in our weather - 106 record tie or breaker tomorrow...
 
I see what you guys put into your trucks! Thats quite impressive on your sigs. I think after pulling a 6k trailer yesterday and running at 210-220 temp I should consiter droping dime on my truck before I burn it up? At this running temp my glovebox side gets hot do to heater core pushing hot coolant through it and thats not even running the ac? Also I dont like the smell of gaskits heating up under the hood. GM may say thats normal, and Im sure with that temp you can just about burn bio-fuel but thats not for me right now. I like lower running temps its better on the engine and on the oil consumtion. What would it take to go with a kennedy 9 blade/ low temp clutch and HO water pump?
 
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D Max Blade with any clutch (OEM or aftermarket severe duty) would serve you better than the KD clutch (waste of money IMO) and a 9 blade 20" steel.......I've tried every combo (including the kennedy clutch)........The D max Fan moves more air than any combo......you won't be dissapointed.

JMHO
 
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