PeachParts Mercedes-Benz Forum - View Single Post - W124 climate control vacuum pod replacement

samiam4 · #81 08-19-2006, 10:59 PM

I'm not GSXR ..But:

1. How can I tell if my evaporator is bad? I don't want to reassemble the dash if it's bad.
Visually is there signs of oil residue? That would be leakage.

2. How do I test for no freon leaks on my 134 ac system? Can I use my trusted Might Vac? I've got to replace the receiver / drier (INDY shop charged system a year ago I told me that's why it gets cool but not cold) because it's not blowing cold & thus replace freon but I wanted to test for leaks prior to removing rec./drier.

You can recover the freon, add dry nitrogen to 200# with a bit of R-22 and it will be easy to sniff test for leaks. Beyond that, you should charge the system.

3. I can spin the front wheel of the compressor so I'm assuming it's good. Can I add compressor oil without removing the compressor? How do you know if the compressor is engaging.

You can add oil with the compressor running via the low pressure line (adapter), or even put a squeeze type 1 oz charge (auto zone). If you've got the system open and replace the R/D replace all the o-ring seals and add oil to the dryer plus maybe 1 extra ounce. I don't have the system component capacity handy.

4. Should I go ahead & replace the expansion valve also? I think it's the original but not sure?
You should learn the functionn of all the components. This is not really difficult system. Pump, valve, evap, condensor and a R/D. If you take the system open, I'd put a new expansion valve in it - I got one at the dealership last week for my W124 and it was $44.

I've got a leak in mine- unfound, but a trusted pro checked the evaporator last charge. Now this past week, pressures didn't work out and it's most likely a failed Expansion valve. I'll recover the freon-then...
I'll do o-rings, flushing the system(coils), expansion valve, get the manifold rebuilt, and back flush it first. New oil, dryer and if needed compressor seals. Pull a hard vacuum for 2-4 hours and if it holds. Charge it back up with 1200g of R-12.
Hopefully that will put it in place. I'll look the condensor over really well for oil residue- but I'm guessing an o-ring on the compressor manifold hose.

Michael