AC oil and turning off/on?

[Steelwheel]

My AC amazingly still works, but it does seem to have a small leak - I have to recharge it every few years. This time I put some stop leak in it.

My problem is that it will sometimes randomly turn off. Apparently the compressor kicks off. Most of the time it works fine, just occasionally I will see the green light for the AC disappear, and then air stops getting cold. Sometimes the light will turn back on again on its own.

I did a pressure test and came up with some odd results. When I charged it I loaded it to around 25 psi, as the manual says, but I noticed that when the car is off, the reading is around 60 psi (the normal value should be about 50). Is that a problem?

Anyone ever have an issue like this?

Also, do I need to add more AC oil, ever, unless the AC is disassembled? I was never fully sure about that from what the manual said.

[rkvons]

Originally Posted by Steelwheel

My AC amazingly still works, but it does seem to have a small leak - I have to recharge it every few years. This time I put some stop leak in it.

My problem is that it will sometimes randomly turn off. Apparently the compressor kicks off. Most of the time it works fine, just occasionally I will see the green light for the AC disappear, and then air stops getting cold. Sometimes the light will turn back on again on its own.

I did a pressure test and came up with some odd results. When I charged it I loaded it to around 25 psi, as the manual says, but I noticed that when the car is off, the reading is around 60 psi (the normal value should be about 50). Is that a problem?

Anyone ever have an issue like this?

Also, do I need to add more AC oil, ever, unless the AC is disassembled? I was never fully sure about that from what the manual said.

I don't know why it would randomly turn off. On my vehicles, I notice that the green light is on regardless of whether the compressor is running or not.

As far as pressure in your system, you have a low side and a high side. You really need to see them both at the same time to tell whether your system is running right. The pressure of the low side alone when the car is not running will vary, depending on how hot the refrigerant is in the system. The hotter it is (like 100 degree day and hot engine area) the higher the pressure of the refrigerant.

As far as oil, you should never have to add oil unless some was lost. It can get lost due to a leak, or it can get lost when you remove a part that has some oil in it and you put a new part on that does not have any oil in it. That's just my .

[Tech II]

You don't say what year the vehicle is....

Having to add refrigerant every two years is a real small leak, and would not tend to lose too much oil.....

first thing in the morning, before the car is started, is when you should check the pressure....high and low side should be equal... and they should approximately equal ambient temp.....70 degrees is the magic number...at 70F, pressure will be equal to 70psi.....below 70F, the pressure will be slightly lower.....above 70f, the pressure will increase more.....for example, at 50F ambient, pressure in the system will be 45psi....but at 20 degrees higher, at 90F, the pressure is 104psi.....

Running pressures are a different story......low side should not be around 25 psi, because this can cause the evaporator to freeze....it can cause the compressor to shut off, or "cycle"......

these are typical numbers....at 70F ambient air, low will be 35-40psi and the hi will be 145-160psi.....If your pressures are lower, you need to add more refrigerant...