A/C question

[Jeremy4601]

Apologies if this is in the wrong spot…

I’m having some trouble with the a/c in my 2002 LT. I have had to charge the a/c about every other summer for some time. I’ve always avoided any “stop leak” additives or anything like that. Last summer when I went to have it charged I was told that the rear evaporator was leaking and quoted well over $1000 for the repair. I had the system charged, went home and watched a few YouTube videos and promptly ordered a new rear evaporator. Never got around to attempting the repair tho and the a/c blew nice and cold so I didn’t really think about it again. Until the last month or so. No more cold a/c. I picked up some Freon and came home to juice it up a bit until I could get back on top of the pending repair from last summer.

Here is where I am in need of help. When I connect the Freon to the port to attempt to charge the system, and yes it is the correct port, etc… when I depress the trigger on the connector to dispense Freon into the system, it starts to release and then the compressor seems to bind and it literally stalls the engine. This is obviously unexpected, so I immediately disconnected the hose from the port and backed away from the situation. Any thoughts on what this may be a sign of?

 

[UmmScott]

Yeah man... unfortunately you should probably stop at this point unless you are knowledgeable about the AC system..

You need low AND high side pressure readings.
You have probably overcharged it or got non condensables in your system or worse, your compressor is locking up and thats why its stalling.
Your truck calls for a certain amount of 134a. Thats what supposed to be in there, not an ounce or 2 more or less.

You can replace the rear evaporator yourself and have a shop evacuate and charge the system up for you.

 

[UmmScott]

Also, good on ya for avoiding stop leak products.. do NOT use them.

Stop leaks function by turning into a threadlike substance when they get exposed to moisture.
That crap will CLOG your condenser, orifices, expansion valves, etc.
It causes much more harm than good.

 

[swathdiver]

When I connect the Freon to the port to attempt to charge the system, and yes it is the correct port, etc… when I depress the trigger on the connector to dispense Freon into the system, it starts to release and then the compressor seems to bind and it literally stalls the engine.

Too much oil in the system? @91RS

 

[Jeremy4601]

So I had the system checked by a shop. The rear evaporator definitely leaks (as determined last summer). Compressor is seized up. Shop says with the system leaking for so long, the oil levels likely depleted over time causing the compressor to seize. Makes sense to me. The estimate is just over $2200. I already have the evaporator and the new compressor, expansion valve, schraders etc total out to less than $400.

So I’ve been down the YouTube rabbit hole, and I feel pretty confident that (with the acquisition of a few new tools) I can likely repair and even vacuum/recharge this system myself.

Aside from welcoming any tips/advice from you guys, my biggest “dummy question” moving forward is this… The system should have zero pressure after leaking so long. I will confirm this by using gauge(s) @ the low side service port. Does this one pressure reading apply to both front and rear a/c? I would assume that it does, but assuming has let me down before. Lol. I have independent front/rear controls (if that even matters). I just don’t want any surprises when cracking into the rear evaporator or the compressor, ya know?

 

[OR VietVet]

Zero pressure is same for front and rear. If you are going to do this yourself. watch some you tubes video"s" and make sure you flush the entire system. You better be replacing the accumulator and orifices. Replace belt if needed. When you pull the vacuum, leave it on the vacuum pump for at least 45 minutes to an hour. Get all that moisture out of that big system. Make sure you check that it holds vacuum. Good luck. While you have it tore apart, do all seals.

 

[Jeremy4601]

Yes! In process now of trying to make a list of parts including seals. I was just watching a few videos about flushing and am definitely planning to do so.

 

[OR VietVet]

Yes! In process now of trying to make a list of parts including seals. I was just watching a few videos about flushing and am definitely planning to do so.

I have seen guys just shoot air pressure thru lines and condensor and evaporator and say, "It's good enough". Dumb *a*s*s*e*s+!

 

[Jeremy4601]

No, I absolutely see the need for the flush… especially on a 20+ yr old system.

Side note… I’m looking at compressors. I see the ones specifically noted for systems w/ rear a/c and separate controls (which I have), but aside from that are there differences? I see at least two different model #’s referenced on the replacements. Is there a way to confirm?

 

[OR VietVet]

What number do you have and where are you looking for the compressors at? I don't want to read line by line.

 

[Jeremy4601]

What number do you have and where are you looking for the compressors at? I don't want to read line by line.

I’m away from my pc at the moment. I’m not sure what model I have on the truck right now so just trying to be certain I buy the right one. Been looking on RockAuto and locally on OReilys.

 

[OR VietVet]

Lots of options on RA, where I was looking at. When you supply the number you are leaning towards, I can try to help answer question but I don't feel like looking thru all the choices.

 

[Jeremy4601]

What number do you have and where are you looking for the compressors at? I don't want to read line by line.

Was looking on Rockauto. 78363, 815534, and 10000629 are the only ones I see that specifically indicate w/ rear ac separate controls. Just not sure how to make sure I’m ordering the correct one. Should I just break the old one off to confirm before selecting a replacement? Don’t need the truck up and running right now so I have time.

 

[OR VietVet]

I see the one at RA that is Four Seasons 78363 but IMO I would choose the Genuine GM parts and use 1521127. They detail the same and look the same. But, if you take the old off and get the numbers off it and cross them, you cannot go wrong.

 

[Jeremy4601]

I see the one at RA that is Four Seasons 78363 but IMO I would choose the Genuine GM parts and use 1521127. They detail the same and look the same. But, if you take the old off and get the numbers off it and cross them, you cannot go wrong.

I will probably do that just to be safe. I appreciate ya taking the time, man.

 

[johns2008]

What number do you have and where are you looking for the compressors at? I don't want to read line by line.

USS AJAX AR6 70-73 Vung Tau