charging a/c question
Thread Starter
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Mountain Pass
Joined: Sep 2003
Posts: 117
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charging a/c question
I bought the conversion kit to convert my '93 ford from R12 to R134. In the meantime, now that i've got the gauge and kit, i'm going to charge my son's '95 Ranger that has R134 already. it has 89,000 miles on it.
His compressor kicks in and out and doesn't blow cold. I assume this is because of low freon. I hooked the gauge to the low side this morning (i'm a die hard) and it showed about 55 lbs of pressure but then when the compressor kicked in, it dropped a bunch. I bypassed the pressure switch in the system to make the compressor run. The pressure then dropped to zero with the compressor running. I didn't let it run very long being empty like that. My questions are:
1. With the pressure reading zero, i guess it's bound to have a leak somewhere. where is a commong place on rangers to leak??
2. whats the best way to finda leak? use dye and a black light??
3. any other advice on charging would be appreciated. i'm going to try it this evening.
thanks very much, Kent
His compressor kicks in and out and doesn't blow cold. I assume this is because of low freon. I hooked the gauge to the low side this morning (i'm a die hard) and it showed about 55 lbs of pressure but then when the compressor kicked in, it dropped a bunch. I bypassed the pressure switch in the system to make the compressor run. The pressure then dropped to zero with the compressor running. I didn't let it run very long being empty like that. My questions are:
1. With the pressure reading zero, i guess it's bound to have a leak somewhere. where is a commong place on rangers to leak??
2. whats the best way to finda leak? use dye and a black light??
3. any other advice on charging would be appreciated. i'm going to try it this evening.
thanks very much, Kent
Elder User
Joined: Jun 2003
Posts: 886
Likes: 1
From: Houston/Hope BC
The best way to find a leak is with a sniffer or as it is more properly called, a halogenated gas detector. It acts like a geiger counter for freon. I normally give my mechanic $20 to do sniff it for me. You will have to negotiate your own rate. 
Here is more than you really want to have to know:
http://www.ackits.com/forum/categories.cfm?catid=20
GL
Here is more than you really want to have to know:
http://www.ackits.com/forum/categories.cfm?catid=20
GL
Senior User
Joined: Nov 2003
Posts: 108
Likes: 0
Well Kent if you haven't already found the leak look for oil spots. When refrigerants leaks it evaporates but the oil doesn't so you will always find an oil stain where it is leaking. Most leaks in cars and truck will be from O-rings that dry up. Look at all the refrigerant line connection and the connection behind the compressor. I have found over the years that about 80% of the time the leaks are from O-rings.
Soap bubbles also work good for finding leaks.
When you charge the system after you fix the leaks have someone give the engine a little more gas then the normal idle, this will lower the suction pressure and the refrigerant will go in faster.
About 40 lbs on your gauge at a normal idle is what you looking for.
I hope this helps.
Soap bubbles also work good for finding leaks.
When you charge the system after you fix the leaks have someone give the engine a little more gas then the normal idle, this will lower the suction pressure and the refrigerant will go in faster.
About 40 lbs on your gauge at a normal idle is what you looking for.
I hope this helps.
Thread Starter
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Mountain Pass
Joined: Sep 2003
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I could get it to 35lbs and that's the most it would take. I tried increasing the idle, etc. and i waited quite a while. i had to bypass the pressure switch to get the compressor turning. so then it took in freon up to 35lb and that's it. it blows cold but not freezing. is there any way to get more freon in there? Thanks, Kent
Senior User
Joined: Nov 2003
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35 lbs at idle is about right. The pressure should start to drop as soon as you increase the idle. Follow the suction line ( the larger of the two lines and the refigerant line you hose is hooked up to ) back to the compressor. It should be cool, about the same as a cold can of coke you take out of the refrigerator. If not you may have a bad or the wrong orifice tube. Did you conversion kit come with one?
Also did you put the system under a vacuum for at least 30 minutes? Air in the system will also cause it to put out cool but not cold air. You have to have low and high pressure gauges to know for sure. Air in the system will show up in the high pressure gauge with the needle bouncing back and forth with the A/C running.
If you have 35 lbs at idle you should not have to bypass the pressure switch. If you have to bypass the low pressure swith with 35 lbs at idle than you may have a bad pressure gauge.
Also did you put the system under a vacuum for at least 30 minutes? Air in the system will also cause it to put out cool but not cold air. You have to have low and high pressure gauges to know for sure. Air in the system will show up in the high pressure gauge with the needle bouncing back and forth with the A/C running.
If you have 35 lbs at idle you should not have to bypass the pressure switch. If you have to bypass the low pressure swith with 35 lbs at idle than you may have a bad pressure gauge.
Thread Starter
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Mountain Pass
Joined: Sep 2003
Posts: 117
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Thank you very much!! It's been two days and the a/c is still working. I'll check the line tonight but i think it is cold like you said. My conversion kit did not come with an orifice tube....but i bought the conversion kit for my '93 and this is a '95 which is my sons truck and it had R134 in it. So i didn't pump the system down or anything like that. i just added the freon. yes it makes sense that there might be some air or something in the system. Now that it has 35 lbs in the system, the compressor only kicks in and out like a normal Ford under driving conditions. at idle it doesn't kick out anymore so i guess the pressure switch is o.k. I'm kinda enjoying learning about a/c. I'm very tempted to check into the price of gauges and a recovery system. I'd be interested in doing a/c work. It doesn't seem to hard when you learn the basics. Thanks for your help, KS
