North American Turbocoupe Organization

Full Version: A/C check, repair-Where to start?
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I have been busy fixing the 88 turbocoupe and have had a couple great drives to work so far this week.  I now am ready to start repair of the A/C system.  Currently when the A/C is turned on...nothing happens.  
No clutch engagement on the compressor
No secondary fan (radiator).  The coolant fan does come on when coolant (antifreeze) has reached appropriate temperature.  
No cooling. Fan blows (vent, mix, windshield, etc.) so dash controls work. 
I suspect no freon, or compressor is dead...
But, it could be something as easy as a relay or some electrical connection, couldn't it? (not that electrical is easy), not that versed in electrical troubleshooting. 

Anyways, like the subject states, Where should I start with an A/C system with most everything unknown...not even sure if it was ever converted from R12 to 134a.  I read and will re-read several more times the article on R12 to R134a conversion and will follow it to the letter when/if that time comes. 

Thanks in advance for any and all advice.
(08-08-2019, 03:35 AM)It 94VERTiGO Wrote: [ -> ]I have been busy fixing the 88 turbocoupe and have had a couple great drives to work so far this week.  I now am ready to start repair of the A/C system.  Currently when the A/C is turned on...nothing happens.  
No clutch engagement on the compressor
No secondary fan (radiator).  The coolant fan does come on when coolant (antifreeze) has reached appropriate temperature.  
No cooling. Fan blows (vent, mix, windshield, etc.) so dash controls work. 
I suspect no freon, or compressor is dead...
But, it could be something as easy as a relay or some electrical connection, couldn't it? (not that electrical is easy), not that versed in electrical troubleshooting. 

Anyways, like the subject states, Where should I start with an A/C system with most everything unknown...not even sure if it was ever converted from R12 to 134a.  I read and will re-read several more times the article on R12 to R134a conversion and will follow it to the letter when/if that time comes. 

Thanks in advance for any and all advice.
I have completed this conversion back in January 2014; I understood basic A/C theory then, read and re-read the R-134a conversion article many many times.

I’ll be happy to assist in any way I can, as I’m sure others will too.

The first thing you’d normally want to do is try adding Freon to see if the compressor now comes on, along with the Primary cooling fan. The problem with this is that R-12 is no longer sold to anyone without a special license, so that complicates things. It would probably take a can or two to determine this, anyway.

Since your ultimate goal is to have functioning air conditioning, might I suggest that you go ahead with the conversion to R-134a. Hopefully afterwards everything will work as it should; if there is a problem this is a good time to find that out.

FYI, here is what I found to be the minimum requirements to undertake this conversion:

1) Vacuum pump—around $100 at Harbor Freight. The one I got in December 2013 still runs as it should. Be sure to use the 20% online coupon at harborfreight.com; just go to that site on your phone and have them scan the barcode found there.
2) A set of A/C gauges—also, Harbor Freight, about $130. Same note on the coupon—this will have to be a separate transaction. (When I purchased my engine hoist and engine stand in December I bought the hoist first with the coupon, had them take it to the car, then went back in and bought the stand with the same online coupon).
3) Several cans of R-134a, WITHOUT compressor oil. Better to add your own (you’ll be draining the oil from the compressor, measuring it, and putting that fresh amount back in).
4) An adapter to connect the R-134a can to the yellow center hose of the gauges. Should be available most anywhere.
4) Compressor oil, 1 small 8 oz bottle. You want the ESTER stuff. (I have pictures of it—I got mine at O’Reilly’s Auto Parts).
5) System flush. You’re only flushing the evaporator (in the car), condenser (by the radiator) and the lines. You DO NOT FLUSH THE HR-980 COMPRESSOR! You’re going to be replacing the Orifice Tube (silver tube by the compressor) and the Receiver/Drier (Accumulator, in some documentation). 1 or 2–16 oz cans is good (I think they’re 16 oz.)
6) You might have great difficulty in locating a new Receiver/Dryer. I have the information to locate one through O’Reilly’s; you’ll also need an adapter to get that one to fit, I also have that info.
7) The aforementioned Orifice Tube. This should be readily available.
8) R-12 to R-134a adapters. The R-134a fittings are bigger than the R-12 and screw right on to them. BE WARNED that some are designed not to be removed once installed. This is to prevent you from going back to R-12, I guess.
9) The o-rings that R-12 uses are black. You’ll need some light green ones, that as it turns out are compatible with both types. They’re inexpensive, so get a few—not too many, because I have read that they can deteriorate over time with exposure to the atmosphere.
10) Patience. This should take a couple of hours, IF it all goes as planned.

There are much more difficult jobs you’ll likely attempt with your car. I would suggest that if you don’t understand or are unfamiliar with a/c theory, you might want to read up on that, it can be a big help.
Thank you so much for that well thought out plan. That is exactly what I was looking for. I have the suspicion that converting to R134a will get the system up and running. I think the car just sat too much the last few years the PO had it and the A/C system leaked the refrigerant.

Like you stated above, I guess there is no other way to determine if the compressor or other related parts are any good unless I go ahead and either 1. Charge with R12 and hope that it will work or 2. Perform the conversion to R134a? If after the conversion to R134a it does not work, it will be no worse off and it will be easier to re-charge (if needed).
I will go with option 2.
Thanks again.
(08-08-2019, 11:25 AM)94VERTiGO Wrote: [ -> ]Thank you so much for that well thought out plan. That is exactly what I was looking for. I have the suspicion that converting to R134a will get the system up and running. I think the car just sat too much the last few years the PO had it and the A/C system leaked the refrigerant.

Like you stated above, I guess there is no other way to determine if the compressor or other related parts are any good unless I go ahead and either 1. Charge with R12 and hope that it will work or 2. Perform the conversion to R134a? If after the conversion to R134a it does not work, it will be no worse off and it will be easier to re-charge (if needed).
I will go with option 2.
Thanks again.
Well in my mind it makes little sense to attempt R-12. I’m sure you can find some place—like an A/C shop—that has a few small cans left over and would probably give them to you, likely for free. But the A/C operation is a sealed system; Freon never wears out, so the only way it can stop working—unless the parts fail—is if it leaks out. So even if you did replace the R-12, the system has stopped functioning, so I think it’s just tick-tick-tick until it would fail again.

Again, there is no readily available source for R-12. I struggled with this decision for 15 years before I finally made the switch. I can’t say I should have done it back then, because the popular opinion at that time was that the HR-980 compressor could not handle the R-134a, necessitating a very costly modification to another compressor (I looked into that and almost did it). Years and many owners, like myself, have proved that is not true.
When I picked up my TC last year my a/c didn't work either so I just installed the 134 adapters and serviced it up with 134 and still working even at 6000 RPM's here in West Texas. I figure since it didn't work before I didn't have anything to loose.
I just bought some adapters too and was wondering if I could just use some a/c pro ???? I thought I read something on here about needing an orifice tube or canister of some type added to the a/c system to work w/the current
134....
I just used 134 that contain oil too.

My A/C had no pressure so the clutch would not come on until I filled it up. Got over 5 thousand miles and the A/C still has cold air to date.
Nice to hear all of the success stories. I hope to pick up the gauges Friday or Saturday (hoping to find some I can borrow) and get started on the conversion. I will post the action when it happens, probably some time in the next week.
Anyone have a part number for the accumulator/drier that they used when making the conversion to 134a? I looked at O'reillys and Autozone and O'reillys didn't have anything that looked like mine, Autozone had one that looked like mine, but it was not available. It was a Four Seasons A/C Accumulator 55630, not 100% sure the line was bent to match the turbocoupes but it looked close.

The autozone part said it was compatible with both r12 and r134a in the description, so why is it necessary to change it out? Is it because it has been in contact with r12 and the dessicant is contaminated?

Oh, and Autozone loans gauges, pump, and spring coupler tools. I had already gone to Harbor Freight and bought the vacuum pump, so I guess I will keep that, but it is nice to know that they are available for free (payment refunded when tools returned).
Thanks,
Neither R12 nor the old white mineral oil will hurt the oil you use in R134A. What hurts it is water. The refrigerants themselves are very much inert and they don't care what's in there. The dessicant absorbs water, that's all. It's good to change it because the oils used with R134A are so sensitive to moisture, but it may not be necessary. R134A liquid is immiscible with white mineral oil. That's it. That is why people use a different oil with 134A.

If you want it replaced, you may find that somebody will cut it open and replace the guts and close it back up. I'm not sure about that.
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