93 Suburban A/C Compressor Help

[PatrickJunior]

Ok..

My compressor does not come on when I turn on my A/C..

Last year we did some test and jumped the compressor straight to the battery and it came on. Filled it with frion and worked, but only for a couple days but I didnt noticed back then because summer was basically over..

NOw, today I went out to look at it and when I turn my A/C on hot air comes out and my compressor does not come on, but I know it works.. any suggestions..

[turkey28]

Sounds like you have a leak. The compressor won't run without enough freon in it. You will have to find the leak and have it fixed or buy a bunch of freon

[Cusser]

For AC work and troubleshooting, you really need gauges. Whether your '93 is R-12 or R134a like my '94, compressor won't engage unless the refrigerant pressure is high enough to activate the safety switch on the accumulator. Since you had a leak last year, and just added refrigerant, you still have that leak, leaks don't heal. Unless you have facility to add some refrigerant and find the leak (using UV dye, soap bubbles, or electronic detector), you're wasting your time. If your '93 has dual air, then you've got even more hidden places where there could be a leak. Your R4 AC compressor is not a great-engineered part, prone to body leaks, or your front compressor seal might be leaking. In 2009 I had to replace my manifold line assembly, there was leakage at the high pressure hose crimp (oily leakage very apparent). Last month I bought and installed a new OEM Delphi compressor (about $190 at AutoZone, special order) and accumulator, my compressor (same as yours) had a belly leak, not a drop of oil left in it.

[turkey28]

My '99 had a leak in the rear air. I had the dealer just disconnect it because it was to expensive to fix. The front air alone worked fine for me, but I never had anybody in the back.

[mishalah]

Originally Posted by turkey28

My '99 had a leak in the rear air. I had the dealer just disconnect it because it was to expensive to fix. The front air alone worked fine for me, but I never had anybody in the back.

Ask cusser how a Suburban in Phoenix works without rear air.

Anyone ever have any luck with a/c "leak sealers"?

[j cAT]

Originally Posted by mishalah

Ask cusser how a Suburban in Phoenix works without rear air.

Anyone ever have any luck with a/c "leak sealers"?

never ever use those a/c leak sealers .no no no !

use the method as described previously to locate leaks...

with older units the oil does reduce in the system ..adding oil if leaking at the compressor seal may stop refrigerent loss..

adding the correct oil is most important ,,,mixing diff oils is not to be done ..

[mishalah]

Originally Posted by j cAT

never ever use those a/c leak sealers .no no no !

use the method as described previously to locate leaks...

with older units the oil does reduce in the system ..adding oil if leaking at the compressor seal may stop refrigerent loss..

adding the correct oil is most important ,,,mixing diff oils is not to be done ..

I agree with that, but I was thinking more of the refrigerant "sealers"....the ones that claim to renew the various seals and stop small freon leaks. Any luck with those?

[MT-2500]

Originally Posted by mishalah

I agree with that, but I was thinking more of the refrigerant "sealers"....the ones that claim to renew the various seals and stop small freon leaks. Any luck with those?

Do not use that crap/junk unless you want to kill the hole thing.

[Cusser]

NEVER use ANY sealer or special chemicals inside an AC system, EVER. Refrigerant, the correct amount and type of refrigeration oil, and maybe UV dye ONLY.

As to only having front air in Arizona, interesting question. From 2000 through 2009 the dual AC (factory R134a) worked fine in my 1994 Suburban, did go through several R4 compressors though. In mid-2009 the rear AC stopped cooling, blower still worked, so I figured that the rear expansion valve was clogged. I took off all the interior panels, and read the TSB about cutting open the rear evaporator case for access. Through all this, we drove through Arizona to Huntigton Beach in early September, was fine. After that Mrs. Cusser never complained about it not cooling enough even when she drove six adults 20 miles cross town when it was about 114F; I asked if anyone complained about the AC, and she said some complained it was too cold. Since my kids are in college and it's very rare for us to have passengers in the back (I ride in it maybe three trips a year) I have decided to leave the rear unit as-is, and just go with the front. So mine is still connected, just no refrigerant passes through that rear expansion valve. My amount of charge is still the same, just it's the front unit only that works. Since the '94 Sub (200K miles) is worth about $2000-$2500 tops, it's not worth having a mechanic fix it for $1000, and I'd sure be mad at myself (and then have to find a way to cap it off) if I really busted something inside that rear unit.

[mishalah]

Originally Posted by Cusser

NEVER use ANY sealer or special chemicals inside an AC system, EVER. Refrigerant, the correct amount and type of refrigeration oil, and maybe UV dye ONLY.

As to only having front air in Arizona, interesting question. From 2000 through 2009 the dual AC (factory R134a) worked fine in my 1994 Suburban, did go through several R4 compressors though. In mid-2009 the rear AC stopped cooling, blower still worked, so I figured that the rear expansion valve was clogged. I took off all the interior panels, and read the TSB about cutting open the rear evaporator case for access. Through all this, we drove through Arizona to Huntigton Beach in early September, was fine. After that Mrs. Cusser never complained about it not cooling enough even when she drove six adults 20 miles cross town when it was about 114F; I asked if anyone complained about the AC, and she said some complained it was too cold. Since my kids are in college and it's very rare for us to have passengers in the back (I ride in it maybe three trips a year) I have decided to leave the rear unit as-is, and just go with the front. So mine is still connected, just no refrigerant passes through that rear expansion valve. My amount of charge is still the same, just it's the front unit only that works. Since the '94 Sub (200K miles) is worth about $2000-$2500 tops, it's not worth having a mechanic fix it for $1000, and I'd sure be mad at myself (and then have to find a way to cap it off) if I really busted something inside that rear unit.

I thought my AC was doing fine, but then it started getting warmer and warmer...to barely cool. Obviously I've lost enough refrigerant to keep it from blowing cold. I thought I put dye in when I recharged it in December, but maybe I didn't because I can't see any leaking spots. I'll try it again, but I have two other questions:

1- the compressor seems noisy to me. Not rattling or squeeling, but just very noticeable when it kicks in (bbbbbbbbbbrrrrrrrrrrrrrrrrrrr....). Not sure I can check oil level without removing it, but I could also add an oil charge...but don't want to overfill. Do all these compressors sound like this?

2- I have full fan control in both front and rear, but when the fan is on high it is very noisy...and doesn't seem to put out much volume of air. All of my other vehicles push more air through the vents than this truck. With controls at full dash vents I can't even feel the center vent hitting me in the driver seat. It sounds like I should be getting blasted, but it's like a kid blowing kisses. Is there a filter or something that may be blocking the air?

[Cusser]

No air filter on a '93. I wonder if your evaporator is clogged (due to a leak) and the refrigeration oil has mixed with dust to block it, might be the cause of both your problems. I think a specialty auto AC shop could use an electronic sniffer to see if the evaporator is leaking.

Maybe your fan blower cage is loose on your blower motor shaft, causing the noise and low air volume???

Those R4 compressers are also known to "belly leak".