Loss of AC oil at lower evaporator conection - How to refill?

[Robert W.]

I had a bit of a scare last night when, 30 min after having driven my 66 roadster for a short checkout ride and parking it in the garage, I heard intermittent hissing (almost sounded electrical) and faint smoke coming from under the hood! After grabbing a fire extinguisher, I opened the hood and disconnected the battery. The intermittent hissing and a dripping sound continued and on the passenger side I saw a pool of oil forming along with louder hissing. It turned out to be the AC connection between the evaporator and the expansion valve. I gave it a 1/4 turn with a wrench and all hissing stopped. It was actually pretty loose.

Now my problem it that I've almost of the oil from the evaporator as well as most of the refrigerant. How do I refill the evaporator with its oil (~3oz)? This was on a brand new rebuilt system too! Also, it funny how a few oz of oil looks like 3 gallons when your trying to clean it up!

[John F.]

Re: Loss of AC oil at lower evaporator conection - How to refill?

Take it to a reputable a/c shop and have them evacuate and recharge.

[Tom L.]

Re: Loss of AC oil at lower evaporator conection - How to refill?

With a proper hand pump it can be done without evacuating. Are you sure it's 3 oz? a little looks like a lot as you mentioned. If only a small amount it may not be worth the $$. Honestly, the only way to know if you have enough oil is to recover the refrigerant, remove the compressor, dump the oil and measure the quantity, if the correct amount put it all back together, if short of oil, add.

On the other hand, if the compressor was ever changed you could go through all that and find out that there was too much oil in the system. The reason I added this is that more than once I've been on calls for commercial refrigeration that had oil return issues. Once the real problem was corrected, usually poor piping practices, I've had to remove oil from the system because techs just kept adding oil rather than correcting the root problem. It's a crap shoot.

[Larry M.]

Re: Loss of AC oil at lower evaporator conection - How to refill?

Robert:

Which refrigerant and which oil are you using?? R12 or R134a?? Mineral oil or Ester or PAG??

There are a couple of ways to add oil to a charged system. One as Tom just mentioned. Another is that depending on refrigerant and oil, you can buy small cans of oil and refrigerant to add to your system. About 1-2 oz of oil per can.

Hopefully the person who initially charged your system is still around. He could do as mentioned above, or discharge/recover the refrigerant, add some oil into the system, pull a vacuum and then recharge to the correct amount of refrigerant.

Tell me more about your system and what refrigerant and oil you are using. Then I can help better.

Larry

[Robert W.]

Re: Loss of AC oil at lower evaporator conection - How to refill?

Thanks for the help! The "new" system is r134a with ester oil. It turned out almost all the refrigerant had leaked out, so we added 2oz ester oil as described and then recharged, System works great now!