[Verdoro 68]

Now that my new engine has settled in I’m going to recharge the a/c system on my ‘68. First time doing it myself.

I replaced the drier, compressor and all the hoses but am a little confused as to how much oil to add in the system. I believe the system on the whole takes 11.5oz.

The compressor had a tag that stated it was filled with 3oz of oil at the factory. Do I need to pull the compressor off the car and add another 6.5 oz of oil to the compressor or should I add less since I’m reusing the evaporator and condenser? Will the compressor even hold that much oil?

FWIW, I’ll be using 134a and a POA eliminator with compressor cycling. The system was filled snd functioning with 134a before I took it apart.

[gto4ben]

Here's a list of oil amounts to replenish per component replaced. Ignore the legacy note on how they use to prefill the compressor with nitrogen and mineral oil. That's how they insured no moisture entered the compressor during storage

The A6 compressor can indeed take the full 11.5oz in it's sump. With the condensor (1), Evaporator (3) and new compressor (3) adding to 7, you'll need to add 11.5-7=4.5 fl. oz. more PAG oil for the system. Confirm the new compressor was prefilled with oil compatible with your intended refrigerant.

[Verdoro 68]

Thanks! I ended up draining the compressor and refilling it with 11.5 oz of oil. Looks like I’ve got the system overfilled now based on your chart.

The good news is I haven’t charged it yet, so I can just drain some oil from the compressor.

[BB70]

I'm assuming you're just replacing the parts for maitenence reasons. I've always drain the old compressor into a cup, rotate the clutch hub to try to get all the old oil out. Drain the new compressor the same way. Put new oil back in the new compressor suction port, the amount you drained out of the old and add a ounce. Rotate the hub until you see oil in the discharge port. Add 2 oz into the new drier. Put it all together and rotate the hub some more. You don't want a load of oil sitting in the compressor when it's first engaged with the car running.

[Verdoro 68]

I remembered that I had a leak at one of the drier fittings before I took it apart which dripped a bunch of oil in the valance so the system was probably low on oil when I took it apart, but I drained couple ounces out of the compressor anyway. I pulled a vacuum on the system and let it sit over night. No leaks!

I went ahead a charged it with 134a this morning. It's supposed to be 100 today, so I figured I better do it before it gets too hot. I have a little over 48 ounces in it now. I read that you want to have about 80% of the R12 capacity (4.125 lbs) in the system which I equate to around 52oz so I should be in the ballpark in terms of freon. I boosted the RPMs to about 1500 to get the compressor really going while filling the system.

At the gauges I'm seeing 25psi on the low side and 275psi on the high side. I wasn't seeing the pressure on the low side go up any more as I added freon so I stopped putting it in. I think you want to see at least 30 on the low side, is that correct?

At the vents I'm seeing about 42-45 degrees. Not as cold as I would like it, but with the POA eliminator and 134 I guess that's acceptable.

The POA eliminator has a good bit of condensation on it and the TXV looks and feels fine. Curiously I'm not seeing the compressor cycle and I have to turn the system completely off to get the compressor to turn off once I turn on the A/C. When I flip it back to vent after resetting, the compressor is off. I must have somehow hooked up the POA eliminator/cycling kit incorrectly.

The garage was 98 degrees when I was charging the system - whew. The engine temp climbed a bit, but held it's own pretty well for being in a garage with minimal air flow aside from a big fan. All in all, seems like the A/C is working. The process of evacuating and charging the system was less mystical than I imagined.

[Verdoro 68]

Figured I’d check the pressures again this afternoon now that it cooled off a little bit (82 vs 95 degrees).

At idle, the low side is 24psi and the high side is 235psi. Seems low on both sides based on what I’ve read, but it seems to be cooling ok.

The compressor cycling is working after all. If I run it up to 1500-2000 the compressor will cycle off and the pressure will build up to 45 on the low side and drop to about 160 on the high side. Then the compressor clicks back on and the system will return to 24 and 235.

Took it for a cruise around town with the a/c on - you can definitely feel the drain of the a/c compressor on the engine. Ooof. However, vent temps stayed consistent and the engine temp didn’t bat an eye so I think it’s good to go.