Yet another a/c question....
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Senior User
Joined: Mar 2009
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From: Las Vegas
Yet another a/c question....
I just picked up a 97 F350 with a 460. When the air is turned on, the compressor cycles on and off. It only stays on for two, maybe three seconds, then is off for about fifteen seconds. I have one of those of those hokey guages on the refill can, and it says the pressure jumps when the compressor comes on. Could it be going out on a hi head pressure kinda thing? Could the orifice be clogged? I'll have the freon pulled out, then can get into it, but I was hoping for thoughts and/or opinions. Thanks very much!!!
Fleet Mechanic
Joined: Feb 2006
Posts: 1,776
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From: Lorain County, Ohio
My first thought is that the refrigerant charge is low, but that gauge doesn't really tell you anything. If the gauge actually goes UP when the compressor is running, there is a problem. It should actually drop. Check with your local parts stores and see if you can rent a manifold gauge set. The actual, and accurate, pressures will help pinpoint the problem right away. In this case, knowing the high side pressure is essential.
Elder User
Joined: Feb 2006
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Let's go cheap. Get a can of 134a and fill it until it stops cycling. Then get a good thermometer and stick it in a vent. Open the windows completely and put the A/C on MAX and fan on high. Watch the temp. When it stabilizes, add about 10 secs. of refrigerant. If the average temp drops over the next minute, do it again. Repeat until the vent temp doesn't drop.
Or if you have a spare $200 around, take it to an A/C shop.
But if you're like me, and do 100% of your own repairs, the first way works better. I don't do it that way anymore cause I'm licensed and have the gauges, but I certainly understand those that just need a quick charge. The A/C shop will charge the big bucks because if they work on it, and it needs charged, then they have to assume it has a leak. So since they are licensed, by law they have to evacuate the system, locate the leak, and repair it. Then they fill the system with new refrigerant, and you get no refund for the refrigerant they recovered from your system (The law allows "topping off" but normally shops won't do that. There's not much money in it.)
Or if you have a spare $200 around, take it to an A/C shop.
But if you're like me, and do 100% of your own repairs, the first way works better. I don't do it that way anymore cause I'm licensed and have the gauges, but I certainly understand those that just need a quick charge. The A/C shop will charge the big bucks because if they work on it, and it needs charged, then they have to assume it has a leak. So since they are licensed, by law they have to evacuate the system, locate the leak, and repair it. Then they fill the system with new refrigerant, and you get no refund for the refrigerant they recovered from your system (The law allows "topping off" but normally shops won't do that. There's not much money in it.)
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Senior User
Joined: Mar 2009
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From: Las Vegas
Hmmm...that sounds like a workable deal. Interesting it may just be a low charge. I may put a can, or a little bit of a can in it and start checking some things. I have a buddy that does commercial a/c work, so I may ask to borrow his sniffer. Maybe I can get a little in the system, and give it a good sniff to find the leak. I really do want to repair it correctly, meaning that I don't want to just add freon when it starts blowing warm. But as mentioned, these repairs can be very costly if left to a regular shop. I have a little time, and even less money...so I think I'll ease into it...lol. Thanks very much for all the help guys!
Al
Al
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Joined: Feb 2006
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What the pro's won't tell you: Many times when a system is low, leaks are never found. Refrigerant will leak out of even the best of systems.
It is 99.9% chance its a low charge. If you do borrow the sniffer, get his gauge set too. Then you'll know for sure.
It is 99.9% chance its a low charge. If you do borrow the sniffer, get his gauge set too. Then you'll know for sure.
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