W210 AC Compressor oil fill issue
 

Hello all,

I am working on replacing the AC Compressor in my 1998 E320. I'm using a Nippon/Denso 7SB16C. I've been following the common guide available here:

W210 E430 AC Compressor Replacement Write-Up - Mercedes-Benz Forum

I got to the part of filling the new compressor with oil and I'm a little stumped. I'm also hoping I didn't destroy my new compressor. Two available sources for the oil capacity for that year car and this compressor said it needed 120ml of the PAO68 oil. I checked for old oil, but only a little bit of oil came out and it came out of the smaller line hole. I checked all over but couldn't find any fill procedure for that compressor. Since the little bit of oil poured out of the smaller line hole, I poured 100ml of oil in. When pouring in the last 20, it got completely full and would not go down any more, even when I rotated the compressor. I assumed at this point there must have been oil in the compressor, so I begin trying to drain it, but hardly 10ml of oil has come out even from me tipping it upside down, rotating the pulley, etc, but nothing. So now I'm wondering where all the oil I poured in there went and how to get it to drain.

I'm now reading I might just need to check how much oil was in my old compressor and duplicate that amount in the new one, but I can't get any oil out of either one.

So tell me, did I ruin my new compressor already, oil where it wasn't supposed to go? If not, does anyone know how I can get the oil of of this one completely? If it makes any difference, I am changing the drier as well.

Thank you!

If the old compressor failed badly, you will need to flush system out in order to protect new compressor from damage. Here is my method that we do at our repair shop.

Evacuate System
Remove compressor, drier, expansion valve or orifice tube.
Fill small amount denatured alcohol into all lines, evap core, and condenser
Blow out with shop air, hold rag on other end of each unit to catch oil and debris.
Install new expansion valve or orifice tube with new o rings, oiled to slip in easy.
Drain new compressor, you never know what or how much, if any oil is in there.
Fill compressor with proper oil as much as you can.
Put remainder of oil in drier and install with new orings
Reassemble everything with new seals / orings
Rotate compressor to distribute oil into lines
Vacuum system to 28-30" vac. For 20-30 minutes
Fill with proper amount freon

Thats what ive done for 15 yrs.
Other than manufacturer defects, no come backs on ac work:o

Hey there, thanks for the info! I definitely gotta flush the system before installing the compressor. You might have noticed in my post though that my main issue is I can't get the oil to drain from the compressor. I poured in ~110ml into the smaller line hole, which I think is thelow pressure side hole, and realized I needed to drain it back out and start over. However, I've gotten barely 10ml from the compressor. I've had it upside down, turned the pulley, etc. And hardly anything. Then I noticed a bolt right next to the line hole that looked like it might be a drain/fill plug. I took it out and only got a few more ml of oil out.

What I'm trying to determine is why all that fluid is stuck in the compressor and how I can get it out.

Turn compressor on its side to drain in a bowl or pan. Leave it there for several hours, turning compressor shaft by hand every so often. Do not reuse the oil. It is hydroscopic. Meaning it absorbs water from the air. It will be useless.
Drain into pan then refill with fresh oil.

Thanks a bunch! I went outside and propped it upside down over a bucket so now I'll wait and see. Once I sort this out, I might just be on the way to my first actual AC Repair. Here's hoping!

sorry to be late here,

on the denso compressors installed on these cars there is a drain bolt for the compressor crankcase, its the big bolt head right next to the electrical connector, thats where the oil is drained from. Make sure not to pour too much oil in there as it can stall the variable device in the compressor suction side and cause it not to start.