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2002 gmc envoy_slt
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Discussion Starter · #1 ·
This weekend I started her up, after about 30 sec or so, I got a weird hissing/howling sound almost like the HVAC actuators had the air in recirc but not really...that's what I thought at the moment.

Later that day, after I started it up, same delay about 30 sec or so, this time it was purging freon and was coming up through the LF fender/hood junction near the windshield. :confused:

After about 10 seconds it stopped and I cannot find any oily residue anywhere. Only thing I can think of is the compressor since it's on that side of the motor. A/C worked fine after that..not as cold but worked, even the 400 mile trip home it worked.

Any thoughts on this?
 

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2002 gmc envoy_slt
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856 Posts
Discussion Starter · #3 ·
I beleive this could be a fan clutch issue, I still have the original with 116K. When I start it, I can stop the fan easily with my fingers...touching the smooth edge of course.

Should I be able to stop the fan and when the fan is working....does it engage with the A/C? I would think so because of the condensor requiring airflow.

So is my fan dead?

Also, I have no overheating issues.
 

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2002 gmc envoy_slt
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856 Posts
Discussion Starter · #5 ·
Will definately get an evac/recharge but me thinky the root cause is lack of airflow over the condensor.

Isn't the consensus that our poor A/C at idle is from the low airflow? Are e-fans a possibility with the 02 models? Before I tackle this i'm contemplating the e-fans only for beter A/C in traffic...not looking for any H.P. gains.

Is there a circuit for the fan clutch to engage with the A/C?
 

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2004 gmc
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26,181 Posts
Poor AC at idle was improved by a PCM flash update around 2005. Dealer-install software. The fan clutch has to be working in the first place, and if you can stop yours by hand, it's bad. The flash update will cost a lot less than efans if all you want is cooler AC at idle. You can run a search and read up on the historical perspective. I tried them and they didn't work for my sort of hot and slow offroading. Others have them and have made a product out a controller.
 

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2002 gmc envoy_slt
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Discussion Starter · #8 ·
Freon is only dangerous in Kalifornia...didn't you get the memo?? :bonk:

When it purged again on me yesterday that's when I noticed the fan barely turning...works when the stat calls for it but barely anything at idle..

I will search the threads for the clutch R&R, what are the best places to get the new one at?
 

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2003 chevy trailblazer_ls
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1,708 Posts
There is an high pressure blowoff valve on the back side of the compressor, but that is on the lower side of the engine. Usually once they open up that is it and all the freon is released. If that opened up you will find the compressor oil around the pipes and valve on the rear of the compressor. You get very hi pressure when the orifice valve/tube gets junk in it.
 

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2002 gmc envoy_slt
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856 Posts
Discussion Starter · #10 ·
First time it vented, it lasted about 10 sec, I had cool A/C all the way back home....bout 400 miles. The third time it popped, it was warm and I have residue on the top of my front diff.

Will get the clutch changed out this week and a fresh charge.
 

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2003 chevy trailblazer_ls
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59 Posts
make sure to get a vacuum pulled on the ac, and it will hold it for 45 minutes or so, if the pressure relief valve opened it may have contaminants in it and will prevent it from closing properly, causing a leak
 

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2002 chevy trailblazer_lt
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3 Posts
having the same exact issue i asked my mechanic at work and he said fan clutch as well. I am just worried of larger issues and dont want to have to replace alot of parts that may not work. did you replace the fan clutch and if so did this fix your problem.
 
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