A/C Has Been Charged

scottewid · 03-22-2001, 11:00 AM

1986 951

Okay, thanks for everyone's help, the fatter of the two lines definitely is the low side and the charging worked perfectly.

Put two cans of r-12 in and now the low side line gets cold, the high side gets warm. Couple seconds after the compressor starts, all the bubbles clear out now. On a 52F day, the vent temp is 44.2F.

Question: The compressor still keeps cycling on for only 10-15 sec, then stays off for 30-45 sec, and the vent temp never gets below 44F. Is this because it's cold out (52F) and a thermostat is telling the compressor to click off because the evap gets to low temp so quick? When it gets hot out, will the compressor stay on longer?
Is this what everyone elses 85.5+ cars do?

My 1990 buick regal gets vent temp down to 28F with the same 52F ambient.

scottewid · 03-22-2001, 05:00 PM

Any feedback is appreciated!

My 1984 na a/c compressor would run all the time, regardless of outside temperature. Just wondering if the 85.5+ system is different because of the auto temp control.

Does everyone else's compressor cycle on off every 10-15 sec in the cold weather?

lm6y · 03-22-2001, 05:06 PM

When the compressor cycles fast, it is usually a sign that it is low on freon. If you are only getting an 8F drop, sit might still be a little low.

Lawrence Coppari · 03-23-2001, 04:32 AM

I charge mine with propane. I've seen it at 43 F on a 98 F day on the highway. Been using propane since 1995 in my old Mercedes. Started using it in 1997 in 944T. No problem so far, and it is cheap. Thermodynamically, it is a better refrigerant. Energy of phase change is greater than F12 by about 50%. Whether it will eat the seals on my system remains to be seen. So far, so good.

scottewid · 03-23-2001, 06:29 AM

Lawrence, you're using straight propane? I thought you had to mix at least 20% isobutane since propane is like r-22 and you'll get too high a head pressure if not mixed...That's interesting that it works straight. I was considering the HC route and using the pre-mixed envirosafe stuff (60propane/40isobutane), but since I still have 5 cans of r-12, figured I'd stick w/that for now.

Anyway, I added one more can of r-12, so I know I'm definitely a bit overcharged now because capacity is 33oz and 3 cans is 36oz, plus what was already in the system. Compressor still cycles on for 15sec, off for 40 sec in ambient of 48F. I suppose this is normal because it's so cold outside, but was a bit concerned because my buick doesn't cycle and you could turn it into a meat locker on wheels in this weather! Guess I'll have to knuckle under and buy some gauges to be sure.

Mrmerlin · 03-23-2001, 07:45 PM

Quote:

Originally posted by scottewid:
Lawrence, you're using straight propane? I thought you had to mix at least 20% isobutane since propane is like r-22 and you'll get too high a head pressure if not mixed...That's interesting that it works straight. I was considering the HC route and using the pre-mixed envirosafe stuff (60propane/40isobutane), but since I still have 5 cans of r-12, figured I'd stick w/that for now.

Anyway, I added one more can of r-12, so I know I'm definitely a bit overcharged now because capacity is 33oz and 3 cans is 36oz, plus what was already in the system. Compressor still cycles on for 15sec, off for 40 sec in ambient of 48F. I suppose this is normal because it's so cold outside, but was a bit concerned because my buick doesn't cycle and you could turn it into a meat locker on wheels in this weather! Guess I'll have to knuckle under and buy some gauges to be sure.

Hi Scott hey it might be agood idea to let out some freon as if the system is over charged it could blow up and bust a line so let some freon out and if your compressor is only cycling a few seconds then you will have to wait for it to warm up as the internal ac temp probe is telling it cut off as it is already at the selected temp........sounds like it is working properly......Stan

Lawrence Coppari · 03-24-2001, 03:46 AM

Actually, it is a mix of propane and isobutane. It comes in a can and seems to work quite well. I purchased it from a hardware store near Nashville, TN. I should not have said propane without anything else. It is an HC substitute that I have been satisfied with. I have thought about hooking my gas grill tank to it and even went so far to get the couplings. But I do not know the purity of the propane I have in the tank. Then there could be a moisture problem.

While driving on I-95 in August in SC with road temperature hovering near 100, the air coming out of the vent above the radio was about 43 F when the cycle quit. It works well for me and seems to leak less. They claim a larger molecule slows leaks.

Oops, I had already mentioned the temperature thing.

[This message has been edited by Lawrence Coppari (edited 03-24-2001).]

scottewid · 03-24-2001, 08:29 PM

thanks everyone for the info!

Ehab · 03-25-2001, 05:45 PM

Hey Guys, I went to a mechanic asking for a recharge for the A/C, but he said that the system in my car is closed, and cannot be charged!!! Could you guys tell me how to do it myself? and which is the preferred refrigerant?
Thanks.

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Lock Stock '84 944 and two smokin' tires ...

Ehab · 03-25-2001, 06:05 PM

It's me again, I read the older thread on charging the AC in a 951, however, I have an '84 944, is the charging procedure different? is the low side line accessible from the under the hood without jacking up the car? My A/C runs cold, but I see bubbles in the glass window, so I just want to top it off.

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Lock Stock '84 944 and two smokin' tires ...

scottewid · 03-26-2001, 04:04 PM

Don't recall where the low side charge port is on the early cars, but on the later cars, it's under the hood right next to the driver's fender. Two aluminum lines with schrader valves, the fatter of the two lines is the low side.

You'll need to get your EPA cert 609 to buy the r-12 these cars take. Go to www.epatest.com to get it online. Once you've successfully completed the test you can buy r-12 cans online on ebay or at www.refrigerantsales.com, and a charging hose. You just hook up the charging hose to the can and to the low side port and charge it with gas. It's pretty expensive for r-12($30 per 12oz can), so you might want to consider one of the alternatives like Autofrost r-406a, or a hydrocarbon blend like Duracool. They work as well or better than r-12, but you have to bring the car to a shop and have it evacuated of all r-12 first. The advantage of these alternatives is that you don't need to change the oil, just evacuate r-12 and charge up with the new stuff. I still had some r-12 cans, so I used that on my car, but will use one of the alternatives once I'm out of r-12.