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Hey guys-
Of course a couple weeks before Rennsport roadtrip AC stops working - been working fine for years.
Here's where I'm at:
Topped up the R12 about 5 years ago when I got a new compressor and receiver/dryer.
I've had the CCU rebuilt by Specialized ECU
When I hit the AC button the light comes on, condensor fan turns on - but no compressor engagement
I've swapped the AC relay - no change
If I jump terminals 87 and 30 at the relay - compressor kicks on. I do get cool air.
So I think refrigerant is just low.
I have cans of R12 along with the little hose that connects to the compressor.
My AC guy I used before - his R12 equipment is broken - parts are NLA
Am calling other places - trying to find somebody with all the R12 stuff...
Not going to convert to 134 before my trip - but I'd like AC.
What would you do?
Options:
A) Just put _some_ R12 in (procedure (?): put can in hot water, jumper the compressor so it engages and put some in. CONS - won't know how much goes in, or how much will be in there in total. How to responsibly deal with the rest of the can of refrigerant? Any tips/BTDT/advice?
B) Pay a shop to do this same thing ( who does have AC experience but not R12 recovery equipment)
Brandon, sounds to me like you are correct, low refrigerant. I have added to my system many times over the years. I would jump the compressor as you mentioned. Add a bit, 5-10 seconds worth, then see if the compressor comes on by itself. Some of today's replacement freon come with a Guage but I'm not sure the hose and fittings are compatible. You might check if the hose, fittings and Guage are available (without the r132). Of course, don't add any gas other than R12. Tom
But... in a pinch, you can guesstimate and get the system working without gauges if you have an instant read thermometer.
Here is the center vent temperature chart. Note that the temperature should be read from the vent at a sustained 2000 RPM with the doors and windows closed, the CCU temperature set to minimum, the fan set to 4, and recirculation on.
Start adding R12 to the system, after a bit the compressor should kick on. Frost condensing on the lines at the compressor can be a sign of low refrigerant, but you're mostly going to watch the temperatures, and compare the outside temp to the vent temp.
Once it's in the range, stop adding refrigerant... your AC should work okay for a while. When you get the opportunity, have the pressures checked by someone with gauges.
Agreed on all points above.
Curious - if system is too low - and holds 32 oz - anybody know how much R12 missing in order to trip the low pressure switch? I have 12 and 14 oz cans.
Once you pierce the can of R12 with that little hose thingy - I assume the gas is all going out - either into the car or to atmosphere (which we all know is not good) - no way to close a valve, right?
So FWIW, I had my system evacuated and replaced with 134. A few years ago. There is a very slow leak somewhere, so i was tired of dealing with R12. The last shop i know that had it stopped selling it, and it was just stupid expensive. Suspect the leak is in the evap but its so slow, its over a year on a charge…
Had the system charged a few weeks ago for a 1000 mile trip in 100 degree + temps and the system worked fine on 134 to keep the cabin comfortable.
Yep - understood. I have several cans of R12 still - I hoarded some off Craigslist after converting to 134 on a previous car (granted it had a Mini York compressor) with lukewarm results - ha ha.
I will probably change over at some point but definitely not before driving out to Rennsport from Denver in 2 weeks.
Brandon
'91 964 Turbo
Originally Posted by Spyerx
So FWIW, I had my system evacuated and replaced with 134. A few years ago. There is a very slow leak somewhere, so i was tired of dealing with R12. The last shop i know that had it stopped selling it, and it was just stupid expensive. Suspect the leak is in the evap but its so slow, its over a year on a charge…
Had the system charged a few weeks ago for a 1000 mile trip in 100 degree + temps and the system worked fine on 134 to keep the cabin comfortable.
So FWIW, I had my system evacuated and replaced with 134. A few years ago. There is a very slow leak somewhere, so i was tired of dealing with R12. The last shop i know that had it stopped selling it, and it was just stupid expensive. Suspect the leak is in the evap but its so slow, its over a year on a charge…
Had the system charged a few weeks ago for a 1000 mile trip in 100 degree + temps and the system worked fine on 134 to keep the cabin comfortable.
So just a datapoint for you.
Spyerx... you happy with the shop that did your conversion? If so would you be willing to share? Was it D&S by chance? Thank you! Joe
Spyerx... you happy with the shop that did your conversion? If so would you be willing to share? Was it D&S by chance? Thank you! Joe
No but he could, actually does he still have/do R12? I never asked him... I'll probalby see if he'll do my evap core when I decide I want to chase this leak
To change it is simple; evac, change valves, replace receiver dryer, pull vacuum, fill 'er up oil/134.
I had BBI do it for me, they have a 134 machine and it's pretty straight forward. Did it while other stuff was being done.
My understanding is that R134a is being phased out.
Now we're going to have to use R1234YF or a hydrocarbon refrigerant.
No experience with either, but still have a little R134a on hand.
I took the car to a local old school air cooled shop to measure refrigerant pressure/add refrigerant - but pressure was was fine. Being an old school shop he happened to have old CCU's laying around - so I swapped one in and voila! Compressor engaged. I circled back with Specialized ECU who had done the CCU rebuild and they were to super quick to turn around the warranty repair. I've reinstalled it and all is good in air conditioned air cooled world.
Datapoint: 5 years on - since I did the compressor replacement and R12 refill - it has not leaked out.
Just in time - I leave for the drive to Rennsport Saturday morning (~1500 miles each way). We're taking 4 days - all backroads/scenic byways. Giddyup.
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R12 AC
