[Searay55555]

My AC compressor pulley bearing recently disintegrated, so I replaced the compressor. 120K miles on an E93. My questions relate to recharging the system with freon.

I bought a Denso compressor that came filled with oil (I think I heard somewhere that it's 5oz). When I installed it, the system had almost zero freon left. I didn't vacuum it but when I pressed the high and low level valves nothing came out, so I assume it was virtually empty.

I bought a "Big Chill" charge bottle, and charged the system to about 42-43 psi. The top end of the "Filled" range on the gauge is 50psi. It doesn't seem to be taking anything more from what I can tell. The can is almost empty, but not completely. My car holds 620 grams. This bottle I bought claims to be 22oz, 624 grams, but I looked at the fine print on the bottle later and it said approx. 19oz of R-134a and 3oz of lubricant. I'm assuming my car wants just 22 oz of pure freon, and not 19oz of freon and 3 oz of oil.

So, my question is, did I make a mistake by adding 3 extra ounces of oil, that is taking the place of what should be 3 extra ounces of freon? Should I have just used the freon without the lubricant? The air is coming out cool, but not the 30+ degrees like some are reporting. It's a Phoenix car so I can use all the help I can get going into the summer. Is there such as thing as too much oil in the system? The capacity of the system is finite, so I assume the ratio is supposed to be just right for it to work optimally. Should I have some of the material discharged/reclaimed to reduce the amount of oil by approximately 3oz, and then fully charge with freon without oil?

Thanks, as always!!!

Kevin

[mainbearing]

Yes, I think you over oiled the system. And you have to vacuum the system before adding refrigerant. Now you have air and likely moisture mixed in there with the refrigerant, and that is not good for the system.

I think it is best to have a shop do it properly for you.

[Searay55555]

When they vacuum the system, do they pull all of the oil out of the compressor also? Or, does the oil remain?

[mainbearing]

Some oil will come out with the refrigerant, because that is how the oil is carried around the system to keep the compressor lubricated.

When a shop uses a machine to vacuum out the system, a catch bottle will tell them how much of that oil got extracted.

Since oil is an insulator, the system will not cool well with too much of it. The shop may have to do multiple plain refrigerant fills and extracts to get more oil out.

Also, if moisture stays in the system and saturates the desiccant, then the metal internals will start to corrode and there will be nothing (since there is no active desiccant left) to stop it. Basically you do not want too much oil, any air or moisture in the system. I would say change the desiccant too when the shop works on it.

Desiccant:
https://www.rockauto.com/en/moreinfo...t=6972&jsn=431

[Twix]

Vacuum doesn’t remove the oil. The refrigerant will boil out of the oil and stay in there. Too much oil isn’t nearly as bad as air/moisture which will wax at the metering device. You should probably use a flush kit, and change the filter drier before putting the system into a good vacuum before recharging.

[sgtfury40]

The vacuum is necessary to draw in the freon when you charge. I just did the exact same repair with the same compressor that came prefilled with oil. I bought AC gauges/manifold with vacuum for around $125 on amazon. There are some good videos on youtube on how to use them. I installed the compressor, vacuumed the system to create negative pressure (so it sucks in the freon and eliminates any "air" in the system) and to ensure no leaks. Then charged the system with a can from parts store that did not include oil and the AC is like new. It's not too difficult.