Automotive Air Conditioning Information Forum

Good morning everyone. New to the forum, glad to find this wonderful resource!

Just began my vehicle AC research, as I discovered a very minimal weep of fluid at my 2013 Explorer’s compressor control valve.

I rented a manifold gauge set from autozone to initially diagnose any issues caused from this small leak, as I don’t know how long it’s been leaking, and there are not spots on the garage floor.

When done checking pressures, I relieved the high pressure hose back into the system through the low side to minimize 134a loss; however, I did not first purge the manifold lines of air. Temp was 87 degrees, humidity 25%. Have I completely ruined any AC components due to this rookie mistake?

I thank you for your time and advice.

As long as you only added the line full of air, no real damage was done.

Obviously you are going to need to repair the leak, and this will mean recovering the system.

Depending on the miles on the vehicle and how long you intend to keep the vehicle the repair could be anything from replacing some O rings to a compressor replacement.

It is leaking oil, so continuing to run it will eventually run the system out of oil. Fixing it before it makes a much larger mess is a good idea.

Do NOT add any sealers or "magic in a can" to stop the leak.

bohica2xo wrote: ↑Mon Aug 07, 2023 9:33 am As long as you only added the line full of air, no real damage was done.

Obviously you are going to need to repair the leak, and this will mean recovering the system.

Depending on the miles on the vehicle and how long you intend to keep the vehicle the repair could be anything from replacing some O rings to a compressor replacement.

It is leaking oil, so continuing to run it will eventually run the system out of oil. Fixing it before it makes a much larger mess is a good idea.

Do NOT add any sealers or "magic in a can" to stop the leak.

Thank you for your reassurance. I agree with your game plan completely. My initial step was to check pressure to ascertain how much refrigerant I may have lost, which may give me an idea how much compressor oil has been lost. Since pressure looked pretty good and my vent temp on max ac is 45 degrees, I figured loss has been minimal.

Next step will be to have system evacuated, and then I will attempt to replace the three orings on my mechanical control valve, which is fully accessible via one snap ring without removing the compressor. I will measure any oil loss during the repair, and add back that exact amount prior to recharge. If oring repair fails, I will buy a new compressor and oil. I plan to purchase a manifold gauge set for the recharge unless the rental is brand new, which they sometimes are, and use a rented vac pump for the leak test and moisture vacuum of the system. Recharge of the specified amount of 134a will then be done AFTER I purge all lines of air. No plans of using any kind of leak stop, as I want to do a proper repair.

Let me know if you see any holes in the approach. I appreciate your help and wisdom.

Before you recover the system, inspect all of the connections for oil leaks. If the O rings on the control valve are leaking, others may be as well.

Rent or borrow a sniffer if you can, and check everything while there is still refrigerant pressure in the system.

The rest of the repair you have already outlined should be good. Adding some oil back to cover a known leak is an inexact process, but in general with a 10 year old SUV sized system with visible oil leakage an ounce of fresh oil is usually ok.

If you do replace the compressor, replace the accumulator / dryer as well.

bohica2xo wrote: ↑Mon Aug 07, 2023 12:46 pm Before you recover the system, inspect all of the connections for oil leaks. If the O rings on the control valve are leaking, others may be as well.

Rent or borrow a sniffer if you can, and check everything while there is still refrigerant pressure in the system.

The rest of the repair you have already outlined should be good. Adding some oil back to cover a known leak is an inexact process, but in general with a 10 year old SUV sized system with visible oil leakage an ounce of fresh oil is usually ok.

If you do replace the compressor, replace the accumulator / dryer as well.

I will add all of this to my action plan. Thanks again for the great advice!

Adding to what has already been discussed, bear in mind that pressures are an excellent diagnostic tool, but they can't tell you how much refrigerant remains in a system. Only by recovering (not evacuating) the charge using a professional machine can tell you that. And when recharging the system, weigh-in the refrigerant using an accurate scale. That's the only way to correctly recharge a system.

If you're getting into it, I would also replace the entire control valve, not just its o-rings. They're relatively inexpensive.

Any parts you might need are available from ACkits.com, this Forum's sponsor.

JohnHere wrote: ↑Mon Aug 07, 2023 1:18 pm Adding to what has already been discussed, bear in mind that pressures are an excellent diagnostic tool, but they can't tell you how much refrigerant remains in a system. Only by recovering (not evacuating) the charge using a professional machine can tell you that. And when recharging the system, weigh-in the refrigerant using an accurate scale. That's the only way to correctly recharge a system.

If you're getting into it, I would also replace the entire control valve, not just its o-rings. They're relatively inexpensive.

Any parts you might need are available from ACkits.com, this Forum's sponsor.

Thank you, I will check out this site. I have contemplated replacing the entire control valve, but won’t be able to identify an exact replacement until I can remove the valve. Fomoco does not list the compressor components any more granular than the compressor itself. I even went to my local Ford dealer for part numbers and he showed me his screen void of any parts diagram regarding the compressor. There is also a screw on the head of the valve that appears to be an adjustment of some kind. Mine is covered over with a clear epoxy, so I’m not sure if the new valve would come pre-adjusted or if that is something I’d have to figure out.

The air in the system is going to add to your pressure readings and inhibit some cooling.

Recover the system entirely, install a new control valve on the compressor, install a new drier, vacuum and charge with a few additional ounces of oil. You're done.

Thanks everyone for the great advice.

nvacnoob wrote: ↑Mon Aug 07, 2023 8:53 pm There is also a screw on the head of the valve that appears to be an adjustment of some kind. Mine is covered over with a clear epoxy, so I’m not sure if the new valve would come pre-adjusted or if that is something I’d have to figure out.

The original valve was "potted," so to speak, using the epoxy, to discourage changing the factory setting. If you purchase a new valve, it will come pre-set and ready to install.