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keeps breaking the belt

mhfd112 on Tue August 03, 2010 1:18 PM User is offline

Year: 2003
Make: Chevy
Model: 2500
Engine Size: 6.0

A buddy called and wants me to try to fix the ac on this truck. He says it keeps breaking the belt. Compressor rattles badly. Blows cool when working. Had someone else look at it before me. That guy changed orifice tube (looked clean) added freon. Owner said it actually blew warmer after the last work that was done to it.

The reason I hesitate to work on this is because I replaced a leaky compressor on a truck like this one once before and it had the same trouble with breaking belts. Owner traded it off before I got a chance to make it right.


Any ideas what I should do?

Thanks,

bohica2xo on Tue August 03, 2010 1:56 PM User is offline

The good news? We know what causes it.

The bad news? New compressor, belt and tensioner.

LOOK HERE for an old thread about just this issue - complete with Video.

B.

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"Among the many misdeeds of the British rule in India, history will look upon the act of depriving a whole nation of arms, as the blackest."
~ Mahatma Gandhi, Gandhi, An Autobiography, M. K. Gandhi, page 446.

NightOwl on Tue August 03, 2010 3:00 PM User is offline

For what it's worth from up here in the peanut gallery. It makes sense that if the compressor is getting ready to sieze that the tensioner would rattle. I would think part of the breaking / shredng belts is either the compressor or the tensioner siezing momentarily and then "breaking" loose. I had a similar problem with an alternator tensioner. Just like the linked thread comments, not long after the replacement the alternator went too.

Have a peanut.

NightOwl,

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Courage is not the absence of fear. Courage is being afraid and doing your duty anyway.

mhfd112 on Tue August 03, 2010 9:34 PM User is offline

Truck owner says tensioner has been replaced twice. Do we still need to replace all three at the same time?

bohica2xo on Tue August 03, 2010 9:46 PM User is offline

A judgement call on that one. If the tensioner is fresh, then probably not.

You can see from the video that it beats the crap out of things - those belts are not easy to break.

The belt may look ok, but if it is damaged internally the customer will think nothing got fixed if it breaks in six weeks.

If this guy is a friend, show him the video & discuss the issues. His money, his call.

B.

-------------------------
"Among the many misdeeds of the British rule in India, history will look upon the act of depriving a whole nation of arms, as the blackest."
~ Mahatma Gandhi, Gandhi, An Autobiography, M. K. Gandhi, page 446.

mhfd112 on Tue August 03, 2010 10:16 PM User is offline

Thanks for the quick reply.

I found another tsb that says liquid slugging is what messes everything up. Compressor, belt, and tensioner. It mentioned putting on an inline filter to prevent the slugging.

mhfd112 on Tue August 03, 2010 10:55 PM User is offline

I texted the guy that owned the first truck like this that I worked on. We put a new compressor on his and it was breaking belts. He said he did put on a new belt and tensioner after we worked on it and didn't fix the problem.

Hope I'm not making this too confusing.

David

iceman2555 on Tue August 03, 2010 11:26 PM User is offlineView users profile

The compressor is normally the main cause of this issue...however, it can be not only be 'liquid' slugging....but also the resultant excessive discharge pressures produced by a restricted condenser. This excessive pressure may result in high pressure/temperature cycling of the compressor....the result is the broken belt.
The days of compressor, orifice tube, flush and recharge are rapidly fading into the sunset...if they have not already.....the majority of severe compressor failures today require that the condenser be flushed with specialized equipment/chemicals or replaced.

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The strongest reason for the people to retain the right to keep and bear arms is, as a last resort, to protect themselves against tyranny in government.
Thomas Jefferson

bohica2xo on Tue August 03, 2010 11:58 PM User is offline

I never bought the "slugging" anyway. This usually happens on 75k miles+ vehicles, and when it is hot.

Never hear the complaint when the customer is using the defroster in march - when the accumulator actually has a bunch of liquid in it.

But once the vehicle has 75k on the clock, the fan clutch is tired. The compressor has some slop in things. The idler is floppy. Things begin to hammer...
.

Ice has a good point about the condensors, eventually every compressor replacement will become a firewall foreward job.

-------------------------
"Among the many misdeeds of the British rule in India, history will look upon the act of depriving a whole nation of arms, as the blackest."
~ Mahatma Gandhi, Gandhi, An Autobiography, M. K. Gandhi, page 446.

NickD on Wed August 04, 2010 12:13 PM User is offline

Hey, with a single belt drive system, couldn't ask for anything more, only one belt to change, makes maintenance a breeze.

But in reality, anything in that belt drive system can be a problem and if it is, you are left stranded, this also includes the harmonic balancer that is no long a solid piece of steel, but has a rubber band stuck in it. In theory at least, if your AC compressor idler pulley is good, can prevent a broken belt merely by switching off the compressor. That may be easier said than done as they don't let you switch it off in recir or if you have to use your defrosters even if you have a compressor on-off switch.

In this vehicle also subtle differences in the belt depending on whether you have the 105 or the 145 amp alternator, the 105 can't hack that extra load.

In dealing with broken belt problems, everything in that belt drive system has to be checked, because either the harmonic balancer, water pump, engine fan, idler pulleys, tensioner pulley, alternator, PS pump, AC compressor, any added emission control devices are all potential culprits, plus their alignment.

Just one culprit, and you are left, stranded, hopefully not on a back road in -30*F weather out of cell phone range.

mhfd112 on Wed August 04, 2010 4:01 PM User is offline

Thanks to all who replied. I'll pass this info along and see what he wants to do. If I do the job I'll let you know what we do and how it turns out.

mhfd112 on Sun August 08, 2010 8:41 AM User is offline

We are going to put a new compressor on.

How much oil should I put back in and can I put it in the compressor? I was planning on draining the new compressor and old compressor and measure what came out of the old to get the amount to put back in.

iceman2555 on Sun August 08, 2010 2:39 PM User is offlineView users profile

The system should be flushed....cleaned thoroughly...and then the correct amount of lubricant should be added to the entire system. The compressor normally requires 2-3 oz....some put 4.... The remainder can be added directly to the inlet side of the accumulator.
Heard no mention about a condenser...but suggest to replace this also......unless the a good closed loop flushing machine and chemical are available. Blow thru is not sufficient to clean this system.
Insure that the evap is thoroughly clean...this is a major reservoir for lube and possible contaminates. Clean the hoses also....

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The strongest reason for the people to retain the right to keep and bear arms is, as a last resort, to protect themselves against tyranny in government.
Thomas Jefferson

mhfd112 on Mon August 09, 2010 6:25 PM User is offline

Buddy says the last guy that looked at it checked the otube and it was clean. If I check it and it is clean can we add a few ounces of oil and put the compressor on?

Does this truck use pag 150?

cc61 on Wed August 11, 2010 8:04 AM User is offline

the reason the orifice is clean is all the debri is still stuck in the condensor!! I would replace the condensor!!

77shovelhead on Wed August 11, 2010 4:37 PM User is offline

Being new to AC repair/service, I have decided that from now on I will make repairs one of two ways.
1. New compressor, accumulator, orifice tube and condenser and flush the evaporator and hoses, or
2. New compressor, accumulator, orifice tube, condenser and evaporator and flush hoses.
In addition to 1&2, check belts, clutch fans and radiator fins.

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Quality is never an accident it is always the result of intelligent effort.

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