Ac help

jmccracken1214

jmccracken1214

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On my truck, the compressor wasnt kicking in at all. I changed the low pressure switch and then it started to kick onfor a second, then off, and repeat. I added a can of freon, which as the can emptied it kicked on and stayed for 10-12 seconds before cutting off then cute back on. The air is cold now but should it be cycling so often?

The pressure gauge goes to about 50psi and then cuts off, goes to about 30 then kicks back on.

Normal?
 
Not normal. Still low


Get the separate gauge and add another can. With it as hot as it is it should charge right up.


Also know there is a reason it was low. Leak somewhere. With the looks of the gas filler. Could be any hose or o ring in the system.

Get a can of the freon with the dye. Then chase the leak.
 
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Make sure you don’t over pressurize it, or it will cycle on and off too. Use the gauge and make sure it stays in the “green” zone. Normally when you hit their seeet spot, they seem to take up gas without increasing the pressure for a bit. Just an observation I’ve made.
 
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At 85-90 degs ambient outside air pressure. The low side should be 45-55 psi.
At 80 degs. --- 40-50 psi.

Make sure you have the AC on full blast and turnt to cold. But not on recirculated or max AC

What truck.? Should only be a couple pounds. If you had it empty.
 
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Mirac said:
At 85-90 degs ambient outside air pressure. The low side should be 45-55 psi.
At 80 degs. --- 40-50 psi.

Make sure you have the AC on full blast and turnt to cold. But not on recirculated or max AC

What truck.? Should only be a couple pounds. If you had it empty.
Click to expand...

96 ranger.
I added a 12oz can of ac pro . With leak stop. Do I need another 12oz can or a small one?
 
jmccracken1214 said:
And as Im adding it, the clutch should stay engaged, correct?
Click to expand...
Yes, or at least not cycle off as fast as it was. If the compressor is not engaged, it can't suck it in.
turn the can up and down to not slug the system either. Upright for vapor, then down a second for liquid. Repeat.
 
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Also, make sure you’re adding the gas to the low pressure / suction side, but I think the connectors are sized so that you can’t add it to the high pressure side.
 
Use a white towel and wipe under the hoses and connectors, the oil is dyed green, easy to spot leaks.
Check the garter spring connections then the peanut connector on the front coils.
Look at the high and low port plastic caps, are they wet with green oil, also look at schrader valves,
sometimes they are not tight, there is a tool to snug them up (or remove if system is empty).
 
noway2 said:
Also, make sure you’re adding the gas to the low pressure / suction side, but I think the connectors are sized so that you can’t add it to the high pressure side.
Click to expand...

That's correct.
 
I'm not sure if it was a known problem but I had the sam truck, bought it new , and just a few months later, the AC line sprung a leak at the ferrule where the hose joined the aluminum line. Hose was pricey then... I just cut the ferrule off s wedged the line and hose clamped it... lasted until I sold the truck 10years later
 
1. All pressures are relative to the interior temp of the truck. There is no set PSI. Depends on outdoor ambient temp and interior temperature of vehicle.
2. Best method is to evacuate the ac system and weigh the amount of refrigerant in by the OEM specifications. You will need a vacuum pump for this method.
3. You have a leak. It may be slow, it may now be quicker than previous but its going to leak out again.
4. Most car/truck leaks are at the compressor seals. These are mechanical unlike a home AC where they are hermetically sealed. If it has dye in the can of refrigerant, a set of leak glasses will reveal a yellow stain at the leak location.
5. The compressor kicks in and out automatically. The low pressure switch will shut it off until the equalization of the pressure brings it back up. Its a safety device for the compressor. Over charge the system and you will f up the compressor. Also overcharge will reduce cooling ability. More is not better.
6. Those cans from a auto store are not answers to problems. They contain dye and leak seal. Leak seal in a refrigeration system is not good for the system. If it was then every home AC unit would have it in from the factory. The metering device to ionize refrigerant can become clogged easily.

If you don't have tools for the proper check of the system I would add a little until the air became cold, while you run the AC on high. If you have the cheap gauge that comes with a can, don't go past the recommend zone- let the interior of the car cool down as you add refrigerant. Add slowly. DO NOT exceed the pressure zone on the gauge once you pull the temperature down to about 75 in the truck. The pressure will be higher due to the car in idle and not moving. Im not a a car AC guy but I am a HVAC contractor and they operate much the same.

I added R134A to my van yesterday. I used a commercial 30 lbs container which does not contain dye or leak seal. My compressor seal has a small three year leak. Not going to change a compressor for that plus it has 235,000 miles. I also made a thermal curtain to contain cool air in the cab and not have to cool an entire metal van full of metal equipment/parts. Man this baby is ice cold in 5 minutes opposed to 25 minutes when its 90+ outside. Good luck.
 
Reminder if the system was indeed empty, you need to find the leak, repair it, replace the receiver drier,
and add new oil to it before you pull a vacuum, verify no leaks, then recharge to specs.
 
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