ac questions...
 

Before last years 10th ann. meet, ac on my 92' was repaired. Two feon leaks were found, and a used oem compressor was installed. The ac worked great for the Indiana road trip, and the rest of the summer.

Last week I turned on the ac for the first time this summer....
The compressor would not switch on....:(

If the freon has leaked out over the winter and there is no (or low pressure); is there some sensor or something that keeps the compressor from switching on?

What should the pressures be (high and low side) when the ac is functioning mormally?

This is a R-12 system that has not been converted to R-22, but this is not a problem. I have 17 cans of R-12...:) :D :D

What do I look for?

As always, thanks for your help!:)

for R12 the low side should be in the high 20s, maybe low 30s, and the high side say 180-200. You know this is outside temp dependent, yes?

yes, there is a sensor that keeps it from switching on, it's the trinary switch located between the drier and the condenser (passenger side, down low beside the radiator). It also will kick the system off with too much pressure - but that's not likely your problem.

Re: ac questions...
 

17 cans?.... care to share???;)

Freon?
 

Almost cheaper to have it converted to 134 than to buy much Freon these days. But, I had a pickup of mine converted and it does not seem to be as cool as with Freon. It cost me $225 to have it converted.

Lee

SVXx4

TOM
 

I wasn't kidding?? I could use a can... how much and I could pick it up at the Denver Meet!!!;):D

I just converted mine to 134a yesterday. It took me ten minutes and cost $35 for the kit.

Cheap
 

Alex

I did not do mine. Had it done, but yours was cheap.
I do not have the gages needed to do it or vacuum pump.

Did you replace all O-rings and the dryer? Also, completely flush the system and put in the 134a compatible lubricant after pulling a vacuum on the system? If you did all of these---that is definitely cheap.

Lee

SVXx4
Did you

No Lee. Mine was already empty. I just turned on the compressor and plugged in the juice to the low side and let it suck it all in. It has the lubricant already in the can. No need for guages or vac pump. It took about 24 oz of the 134a.

Stephen

Uh-oh. What happened to the old mineral oil that was in the system initially? The problem with it - it is not soluble in R134 (was soluble in R12). I guess it is too late now, the main risk you are running is that the compressor seal will start leaking. It may or it may not, kinda gamble.

I don't know. I just followed the directions to the letter. It says its all compatible. We'll see what happens.

Stephen

Is this because there might be too much oil and it's not compressible or ???

I converted mine about three months ago and have had no problems. As long as you run the ac at least 2-3 times a week, the seal in the compressor will stay lubed, and no freon should be lost through the seal.

If you go long periods of time between usage of ac, the seal in the compressor will shrink, or develop a tiny flat spot where it sits most of the time. Then under engine load it spins the shrunken, or flat sided seal, letting freon/oil by, you can see evidence of this on your under hood cover above the ac compressor (if you don't have belt cover on).

The seal might start leaking. I don't know exactly why. I'm having trouble understanding how it might work at all in the first place :)

Too much oil just increases the compressor head pressure and wastes energy. Same about air in the system.

If you have to much oil it can wreck the system. When I did mine. first I removed the compressor and held it upside down while spinning the compressor to drain all the oil out. than unhooked the lines from the dryer and used my air compressor to blow out the lines. put compressor back on car hook up the lines. install the 134a low side adapter. start car turn air on high than start to add freon with the first two cans upside down to activate the system. once you get some pressure built up use something covered with a shop towel to press the valve on the high side service port( it's on the dryer) purge until the air is all purged out off the system and it looks like a co2 fire extinguisher going off. finish filling the system. check with a guage. to much will seize the system. should freeze you out of the car now.

a/c conversion
 

I am in the middle of this conversion on another vehicle so I thought I'll share some info:

-R12 leaked out so the system was empty
-removed compressor and drained all old oil out, also removed one shim out of the clutch. This decreased the air gap which should reduce/eliminate any clutch slippage. I figured this gap gets bigger with age and the R134a runs at a higher pressure.
-replaced the air drier/receiver $35. Keep this thing closed up until you're ready to mount the hoses on. Sucks up ambient moisture rather quickly!
-had a local a/c shop make up a new hose for $40
-replaced all O rings that I have access to in the engine bay. O rings come in packets costing $1.50
-dumped 4 oz of Pag 150 oil in the compressor ($5)
-Using a flush detergent ($15)I used my air compressor to blow the system out. air compressor was set at 30 psi. Lots of old fluid came out of the condenser that's in front of the radiator.
-Hooked everything back up and waiting for a trip to the a/c shop for an evac and recharge.
-changed fittings to the new style ($7)

I basically went though all these steps due to the fact that my vehicle is high mileage. Also, I wanted to squeeze as much btu out of the R134a as possible so hopefully my efforts will be rewareded with a cool a/c. When the time comes, I'll do the same thing on my svx.

Peace.

Ali