Here's my story:

My father had the Camaro's A/C converted to 134A three years ago. What all that entailed...heaven only knows. It was probably a half-way job, but it DID include a brand new (not rebuilt) compressor. It really hasn't 'been right' since, but it was tolerable.

Now my A/C hasn't been working well for over a month. That's to say this--at idle, the compressor would run excessively rough (vibrations), and cooling inside the car sucked (no thermometer...but it was 70 degree air or hotter). At speeds over 10mph, the vibrations would smooth out, and the vent temperature would cool down a little...again, no thermomemter, but I'd say about 60 degrees.

Today I have had enough. I checked the belt to make sure it was tight (it used a little tightening, but not much). Still has the same results. I put a guage on the low pressure side & it read 70psi//what--~75 degrees at the evaperator.

I thought...BINGO. Somebody didn't know what they were doing & overcharged big time. I purged to 40psi. As I did, when I hit about 60psi, the compressor smoothed out (yes, the compressor is still running...but not cycling). Now I'm down to 40-45psi, the compressor is running, BUT...the vent air is hotter than ever, even at 65-70mph.

Does this sound like something is clogged up? Perhaps the accumulator? Cross-Contamination (R12 with 134A)? How can I troubleshoot on? Thanks, guys!

Scott

 

Just a little more information. The line from compressor to condenser is warm/hot. The line from compressor to accumulator is warm/cool (with 70psi, it was cold). I don't feel any lines that are cold.

After startup, the guage reads about 45psi. It goes down to about 35psi & stays there (no changes). The high side is static at about 200psi. I'll get a thermometer & check the vent temps. The compressor is not cycling (it is on//full time). I've discontinued use outside of troubleshooting to avoid killing the compressor.

 

If the compressor isnt cycling there is probably a problem with the low pressure switch. For the system to operate as designed it must cycle.

 

R-134A requires , most importantly, a better condenser, and a higher-volume compressor. It seems to create more heat, but less cooling. This new refrigerant is not as efficient as R-12, and head pressure is much higher. I had tried the conversion, and suffered through two hot summers.
All that I accomplished was to ruin the front seal on the compressor. This was with the correct oil.
Did you know that R-134A has been linked to instant coronary failure, and testicular cancer? Can't say that about R-12. Although the ***** did use phosphogene gas (R-12 exposed to a flame), to kill many people.
I have been using a product called 'Envirosafe'. As an organic (flammable) coolant, it works at VERY LOW head pressure. Furthermore, it cools admirably. Uses mineral oil or ester oil only. Not compatible with PAG oil.
This stuff is environmentally safe, cheap, and is only flammable at an open flame. So is gasoline.
As a huge molecule, it leaks out v e r y slowly.
I have nothing to do with the company. Just very happy with their product.
B.T.W., the a.c. will only cycle until it has run a bit. Your accumulator is probably not the immediate issue. The orifice, though, has a screen on it, which can clog. Unlikely thay you increased low-side pressure by sucking in air, or a genie put in more freon. Also, as I understand it, the compressors are shipped dryWonder if you have lubrication/wear issues, that have clogged the screen. You know where the screen is? Needs a look-see. It is inserted into the bottom inlet tube to the evaporator. The pipe union nut is sort of under the accumulator.

 

Thanks, guys. I know that the condenser wasn't changed out. That might be the big issue as to why it just isn't very cool. I'm going to get a thermometer tomorrow. What kind of condenser do I need to get (manufacturer/pn)? I'd like to replace that before next summer for sure!

Today, after letting it sit overnight, the compressor cycles. I wonder if it was frozen yesterday?? Anyway, that was a better sign. I'll check everything you mentioned, and get a low-down on the temperature & pressure.

Thanks again!!

 

This morning, about 75 out, with the blower on high, on the highway the temperature out the vent was 45 degrees. At idle, it was about 55. That's livable.

But...This afternoon it only hit 85 outside (high humidity, though), the vent was 50 degrees going down the road...60 degrees at idle. If it was one of the 100 degree scorchers, this would suck.

I'm going to clean the condenser & the evaperator this week. Might consider adding an electric fan to the condenser.

 

Was the inline filter changed? I forget what it is called, but it is a long white filter at the base of the accumilator. When I rebuilt my system, I pulled the old one out and it was filled with sludge. My A/C now blows 40 degrees at the vent. Still on R12 though.

Jim.

Edit: Orfice tube filter?

 

ALthough I not sure what the problem with your A/C is. I just did a conversion and I had excellent results 42 degree vent temp on 95 degree day.
I followed this article closely:


http://www.iroczone.com/newindex.htm

It was very helpful

 

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