Hey all,


The only part of a car I know little about is the AC System.

I've tried charging the system twice (was converted to R134) and when the system is about 3/4 of the way charged the ac compessor starts dragging, and the power steering is very, very laggy.

I've been told there might be a blockage of some sort in my lines.

Any ideas or suggestions? This problem occurs with two brand new compressors.

Also, with R134 I've heard to use anywhere from 1.5 to 2.5 lbs of r134

And yes.... I did use the proper amount of oil charge each time (6oz from what the compressor instructions stated)

Thanks in advance!

 

What are high/low side pressures? This type of problem requires a set a guages to properly diagnose. A clogged orifice is one possibility. Was the system properly dried out with a vacuum pump? Lots of possibilities here.

 

Thanks for the tips.

I don't have a vaccum pump.


The only port I know of to put a pressure gauge on would be the port on the top of the dryer/accumulator where I hook up to hose for the R-134 cans.

I'm very tempted to take this thing to a shop and let them fix it. Would very well be worth the cash.

 

Danno is correct in that you need guages to properly diagnose the problem.
Here are my observations and questions with the information you have given:

First, you need to evacuate the system before charging it to remove moisture and non-condensible gasses (air).

Second, you need to install a new accumulator, it has a dessicant /filter in it to absorb moisture that may be left in the system after evacuation, and to stop the huge chunks.

Third, the orifice tube should be replaced with an R-134a tube.

Was the R-12 oil purged (blown out with R-134a, or compressed air) from the system when it was converted?

Reason for question:

1. R-12 oil is incompatible with R-134a.
Small amounts of residual oil will find a low spot in the system and just sort of hide there.
Large amounts wil try to continue to circulate and cause problems. Since it won't combine with the R-134a, when it gets to the compressor, you will have a slug of oil that the compressor is locking on, and causing the belt to slip.

2. If the R-12 oil was not purged, when you added the R-134a oil and the refridgerant charge, you caused a technical overcharge, and that would also cause the compressor to need more power to operate.

3. Did you add another 6 ounces of oil with the 2nd compressor?
Too much oil will also cause problems. (slug of oil, technical overcharge).

4. I HOPE YOU DIDN'T DIS-CHARGE THE REFRIDERANTS INTO THE ATMOSPHERE.:nono: That is a Bozo nono.

5. If you are going to persist in your endevour, get a set of guages and a vacuum pump, and maybe a book.

Oh, one more item, when you convert to R-134a, you only put in 80% of the listed R-12 charge.

 

Yes, the system had been previously evacuated and properly converted to r134.

The previous owner was working on the vehicle and broke one of the ac lines.

When I bought the car he had a brand new line in the back of the car for me. (as well as many other parts)

So basically, not knowing much about AC Systems I instaleld the line, and proceeded to put in about 2 pounds of R134.

I'm betting there might be too much oil in the system.


Will a vaccum pump on the system alliviate that?


I'm thinking today is a good day to just take it to a shop.


Thanks for the help, it is appreciated.

 

A vacuum pump will pull a small amount of oil.

If I were doing it at my job, and thought the system had too much oil, I would evacuate the system, re-charge, operate it and check the pressures, then recover the charge and measure the amount of oil removed from the system with the R-134a.
I have found that most of the time, with the systems I deal with, they only recover about an ounce of oil if the system had the correct amount of oil to begin with. Any more than that, and I become suspicious, and won't add any more oil when I re-charge.

If I knew there was an oil overcharge, I'd purge the condenser, evaporator and lines with R-134a, and replace the reciever/drier, or accumulator, as the case may be, then inject the proper amount of oil during the re-charge step.

If you have the cash and have a shop that you trust, by all means, go there and explain the problem and the history, get an estimate, then tell them to call you when it is done and leave.

My opinion is about 3 hours labor and maybe an orifice tube, accumulator, and o-rings, plus whatever they charge for 2lbs of R-134a. Probably 250 bones. Just my opinion, and I could be wrong.

Good luck with whatever course of action you decide to take.

 

Very good advice.

 

6 ounces sounds like a crapload of oil to me. When I put the PAG 150 in I only put in 1 ounce just to oil up the compressor. The oil in the cans made up for the rest. You have to watch out, some of those R134 cans already have oil mixed into the refridgerant. Too much oil is not a good thing.

 

It's fixed anyhow. Thanks all for your opinions.


Serpentine belt was 2" too long. Was just barely tight enough to run the power steering and alternator. Add the drag of the AC Compressor and instant belt slippage.

Somehow the belt I bought was too big. All my previous f-bodies had v-belts. Oops!

Bout $100 at the local Tuffy for them to evacuate/recharge AC system and replace the belt and put 4 bolts in my air deflector for me. (I could not find the right size bolts, and it only came with 2 bolts.)

 

The belt was to long, go figure.

Glad you found the problem.

 

The system hold 6-8 oz's of oil