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breaking a/c belt


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Posted

Does anyone know why I keep breaking a/c belts. I have went to countless dealers and mechanics with out any luck. This is getting realy old. somebody has got to know. please help.

Posted

Could be the belts. How often are they breaking and what brand are you using?

 

My original belt went over 40k before I replaced it (I still have it as an emergency spare I think). Less than 2 weeks ago, while I had the thing torn apart to install electric fans, coolant, etc. I figured I'd better put new belts on it. The AC belt was cracked so bad that I guarantee that it would have failed sometime in the next few months (at less than 2 years old at that). The main belt looked fine.

 

I also wonder if you're AC compressor is cycling too often. Think about the stress put on a belt every time that compressor clutch engages when the engine's at upper RPM's (2k+).

 

 

Just my .02.

Posted
Does anyone know why I keep breaking a/c belts. I have went to countless dealers and mechanics with out any luck. This is getting realy old. somebody has got to know. please help.

 

 

 

 

 

Are you using a Gates belt?

 

I had the same problem with my 99 z71 last summer. I replaced my A/C belt with one made by Gates and it kept snaping (went through 2 or 3 of them). Found out that GM uses Dayco for OEM went to Advance Auto picked me up a Dayco and it's been going good ever since. Try that.

Posted

I have tried everything I know to do. I have tried oem belts, belts from four different part stores. I have replaced my pulley and tensioner. done a pressure test, uninstalled my hypertech power programer, called hypertech to ask questions, reinstalled it. The funny thing is I cannot find a GM dealership that knows what is wrong. I have been to three in the area with no luck. I have seen in the forum backlog where other people has had this problem but no solutions. My friend suggested recovering the freon and pulling the orfice to see if there is any metal in the filter. He said it might be locking the compressor up. I like the idea about the high pressure being to high. It does seem to cycle to much. What would you need to change? The high pressure switch?

Posted

if your a/c is cold, don't mess with anything. clogged orifice = warm air. wrong pressures = warm air bad pressure switch = warm air locked compressor=warm air.

 

Ken

Posted

I'm grasping at straws here...but you might want to check the power steering pump pulley. The pulley is supposed to be flush with the pump shaft (I think plus or minus .010" but I can't remember exactly).

Posted
I'm grasping at straws here...but you might want to check the power steering pump pulley. The pulley is supposed to be flush with the pump shaft (I think plus or minus .010" but I can't remember exactly).

 

 

 

 

PS Pulley should not have any effect on the a/c belt. It is a seperate belt on the NBS 5.3l .

  • 3 weeks later...
Posted

I don't know the answer, but I do know that I changed the original belt on my 99 silverado at 190K miles and ever since it will break the belt if I leave the a/c on for long periods. If I pay attention to it, the air flow out of the vents will all but go away just before the belt breaks. I'm thinking the system ices up, because if I turn off the compressor I get cold air for several minutes (5-10) and the air flow gradually increases. Been through about a dozen belts since then and it's annoying. Never had a problem until I changed that first belt. Makes no sense to me.

 

I also have an 02 suburban 1500. If the a/c is on and you give it gas the a/c belt tensioner starts slapping really hard against the transmission lines which makes a horrific noise. If you don't immediately back out of the throttle or turn off the a/c it will snap it's belt.

 

On both trucks, I've had dealers and independant shops look at them, and have replaced belts and tensioners several times. Nobody has a clue as to what is going on with them so far.

Posted

As im sure you have more of a problem on hand then just the brand belt that youre using....when you find the fix go with a DAYCO belt...these are suppose to be the best..they even come with free replacement for a year i beleive...a few bucks more but well worth the quality..just put a cheepy next to one and youll see

  • 3 years later...
Posted

I have the exact same issue with my sister's 2002 Suburban dual a/c and a Nippondenso compressor.

 

In the 1980's I worked for Dayco and still like their products but I don't think your up against a belt issue unless your installing one of the low price imports now available. I would use Gates, Dayco or Goodyear. Napa is Gates also by the way. I just installed a Goodyear on my sisters Suburban with the same issue.

 

What I did see is that her High side pressure on the AC goes up by 75psi exactly when the noise starts.

Hers is RPM related. Quiet up to 1500 or so and very noisy from 1600 to 2400 when it quiets again.

Sounds like something banging against tin, quite loud.

 

I pulled the compressor to change it out but it rotated very smoothly and shows no signs of failure. Lines look clean and bearings are in perfect shape. I recharged the system and it is blowing 38 degrees at 1500 Rpm parked.

 

I forgot to check the rear AC temp but I suspect either of the expansion valves is blocked or partially blocked causing the pressure jump when the RPM increases. If the rear AC is warm I found the issue and hope the compressor is still OK.

 

Please let me know what you find in yours.

Posted

If you want to get to the root of the problem...

 

Cameras are pretty small and cheap these days. Maybe mount a camera and light which both point to the compressor pulley area, then run a wire to the inside of the vehicle through the window and attach it to a camcorder. Videotape what is happening!

 

More monitoring would be to attach gauges to the high and low side of the A/C so you could see them and note the pressures when this happens. The only problem with this plan is these hose connections can leak and if left on the vehicle, the refrigerant might all leak out. So maybe connect them, drive around, then disconnect them? Whatever works. Maybe mount the gauges so you can see them through the windshield?

 

Anyway I have had a lot of luck with this type of thing with impossible to solve electronics/electrical problems. You can't see what is going on, so If you can rig something up to monitor what is going on or record what is going on, then you can "catch it in the act"!

Posted

Sup,

 

I am a NAPA jobber selling Gates Belts. 99-05 GM 4.8L, 5.3L, 6.0L Trucks using a 25-040378 A/C belt sometimes have problems. Some truck require a PCM flash to keep them from snapping the gates belt. It is due to the extra cords in the belting in the Gates belt. I think I have a copy of the GM Tech Bulletin at my office....... I will look around tomorrow. I had this problem in early 99..... It was a know issue with gates. I seem to remember it had to do with the compressor clutch engaging upon cranking. The flash makes the clutch wait until the truck has settled the idle down from cranking.

 

However I did not have this problem with my truck... Put a 25-040378 belt and a 38159 tensioner.

 

As always give the pulleys a good check spin the pulley if it keeps spinning more than 3 or 4 rounds replace the pulley or if it wobbles side to side. After installing the belt crank the truck and watch the tensioner and see if its allowing the belt to gain slack (ie moving back and forth). !!!Pulleys that make noise in the alternator, water pump, or A/C Clutch need to be fixed prior to installing the new belt...(not only the A/C Belt... I KNOW its not with the a/c belt on this application)!!!!!

 

If you lay the belt down on its side on a counter it should NOT COIL UP like a double helix from biology class...... If it will not lay down on its side and it was running on the truck... SOMETHING IS A FOUL in the belt system (ie something is broken or getting ready to put you down)!!!!

 

By the way I have warrantied in the last 10 years that I have been at NAPA maybe 3 or 4 belts that was actually a belt problem!!!! New Belts DO NOT SNAP not Gates ones. You have a problem. Might need the flash to make the snapping problem go away...

 

Also, Extra knowledge NAPA Gates has a longer life belt now, take the part number and stick HD behind it... Such as that A/C belt 25-040378HD these belts will be green backed and much tougher.. Theses belts were only AIMED at Fleets..... But they are a MUCH BETTER BELT... even than a regular Gates belt.

 

Jbo

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