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Do i need to flush the AC system out?

I replace a new AC compressor on a 2004 GMC envoy do the AC system need to be flush?

Posted by Joe Russell on


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You do not need to "flush" the AC system, but you will need to put a vacuum pump on it to evacuate all of the air before charging with new refrigerant and the recommended amount of oil charge. It appears that the refrigerant is R-134a and the system takes 48 ounces for a front and rear system or 29 ounces for a front only system. The specified oil is PAG46 and you will need 8.5 ounces for a front and rear system and 7.5 ounces for a front only system. The first link below is the specification page and the second is a video showing how to charge the system. The big parts chain stores will loan or rent the necessary tools and will be happy to sell you the refrigerant and lubricant.

Posted on Mar 19, 2019

  • Kardoc Mar 20, 2019

    If you pulled out the orifice tube you would be able to see if the old compressor has come apart and the system needs to be flushed.



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SOURCE: 2004 GMC Envoy has trouble idling

Try the fuel filter. Sounds like the engine might be running rough due to weak fuel pressure. Its cheaper to replace, especially if it's still original from 04. Try running some injector cleaner through a couple of tanks of high octane gas.

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SOURCE: battery removal on a 2004 GMC Envoy

The battery is on the right side behind the fuse box. You need a metric set to undo the 3 screws. Theres one that attaches to the body, one to the bar that goes along the top, and theres one on the left side below the vacuum hose and air induction. After you've taken out those three, you should lift the whole thing out(battery and shroud) together. It's hard to take the shroud off before you lift the battery out. After that, you have to pry the shoud off the battery. The two terminals in the back make it hard. Then just go to any auto parts store and they'll give you a new one. 

Posted on Jan 28, 2009


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SOURCE: Removing rear air suspension on GMC Envoy

Just behind right rear tire up in the wheel well. Air inlet is inside right rear quarter near the accessory inflator. Compressor runs 3 lines one for the accessory inflator and one for each air bag.
THere are also 2 sensors, one on each trailing arm that senses load and then raises and lowers accordingly.

Posted on Feb 17, 2010


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SOURCE: Where is the cruise control fuse for GMC Envoy

its in the fuse panel under the hood there should be a chart on the cover

Posted on Feb 24, 2010


Ricky Gittins

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SOURCE: I have a 2004 GMC

Hook up a set of A/C gauges and look at this site

Posted on Aug 04, 2011

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