Well I just rebuilt my friend's A/C tonight (1997 E320) due to a seized compressor. I had been planning this for about a week now and want to thank everybody on this forum for their EXCELLENT, EXCELLENT advice. All the info I gathered here made the job go very smoothly. I ended up replacing the condenser, compressor, and receiver/drier, and flushed everything else out with flush solvent and a compressor (except the evap and suction hose, due to difficulty removing and accessing).

The new compressor had oil in it, but I have no idea how much. I tilted it to get a feel for how much is in there; there was at least 2 ounces from my guesstimate. But I really have no idea how much. So I added a UV charge for good measure and hooked up the lines. I was able to put about 1 more ounce into a line going to the receiver/drier; there just wasn't much opportunity to pour more oil in, especially since the suction hose faced downward. So worst case scenario there may only be 3 ounces (?) of PAG in there (keep reading).

Once the system was sealed, I spun the compressor by hand about 6 or 7 times and then pulled a vacuum for about 1 hour (picked up a new economy 1.5 CFM vane pump at McCain's for $150). I spent a half hour refilling the radiator, hooking up the hoses, topping off the trans fluid, etc. and during that half hour the vacuum held with absolutely no drop. So I charged the high side with about 1/2 a can of R134A, and started to put the other into the low side. Then I fired up the car and set the A/C to max.

The compressor immediately kicked in, and I slowly coaxed the remainder of the can into the low side, and then over the next 10 minutes coaxed a second can into the system. At that point the pressures were 35 low, 250 high, ambient temp 90 degrees and vent temp 55 degrees. I know that's not quite where things need to be, but it seems like a good start. The car was still up on jack stands in my garage and not moving when these readings were taken.

Can anyone tell me if everything sounds normal so far? I was going to get a can of 4 oz. oil charge tomorrow and add that, since I have no idea how much oil is in the system. Is that a good idea?

I will say this - I shut the high and low sides off on the manifold, and then disconnected the yellow service hose just to release the pressure, and quite a bit of high-pressure refrigerant escaped from it for a couple of seconds. It was unmistakably bright green from the UV charge I put in it, but it was also VERY OILY. Does this mean I don't need to add any more oil?

I have read that adding too much oil can be worse than too little. Is there any truth to this?

LarryBible, what say you please?

Thanks!

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