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AC problem

Badboy4435

By Badboy4435
in Ask A GM Technician

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Badboy4435 New Member

Badboy4435

Posted
Posted

I have a 2003 GMC Sierra 2500 Duramax that keeps blowing out the Freon from the AC Compressor. I have replaced the compressor 3 times, fan clutch and condenser but it keeps building up too much pressure. What else could be causing problem?

Jsdirt Senior Enthusiast

Jsdirt

Posted
Posted

About the only causes of that would be a severe overcharge of 134a, or blocked airflow across the condenser (or the wrong condenser - too small). Fan installed the correct direction?

 

Before I had a scale and good gauges, I used to charge by feeling the inlet and outlet of the evaporator. Once they're the same temperature, or, the outlet is slightly cooler, that's it for refrigerant - she's full.

txab Senior Enthusiast

txab

Posted
Posted

You should have a high pressure cut-out switch that will shut the pump down before it blows off.

 

Have you put gauges to see what your pressures are?

Badboy4435 New Member

Badboy4435

Posted
  • Author
Posted

All the work is being done by a reputable mechanic but I think he is perplexed on this problem. He has a 4 bay garage with several mechanics working there so i'm sure he has all the equipment for the job.

 

Jsdirt Senior Enthusiast

Jsdirt

Posted
Posted

Maybe they got a batch of chinese 134a, which ISN'T 134a? Time for a sniff test ...

txab Senior Enthusiast

txab

Posted
Posted
2 hours ago, Badboy4435 said:

All the work is being done by a reputable mechanic but I think he is perplexed on this problem. He has a 4 bay garage with several mechanics working there so i'm sure he has all the equipment for the job.

 

Then you need to find someone who knows more about AC or specializes in it. If your guy is perplexed move on.

 

Make sure he's charging by weight and not over charging. Not adding too much oil. Pulling a proper vacuum to boil off all moisture. As noted above counterfeit 134a is a possibility also. There are guys using all kinds of chemical combos out there

 

 

KARNUT Senior Enthusiast

KARNUT

Posted
Posted

I’m a pretty good general mechanic. I’ve used the store low side fill with some good results. There’s so many stupid little things that can be wrong with an AC system. Once a simple low charge check doesn’t lead to good results. It’s best to find an experience AC technician. I almost changed a compressor and condenser. It turned out to be a o-ring. Lesson learned.

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