w124 AC pressures equal across compressor
 

I just got the report from my Air Conditioning shop. The compressor is spinning away like it should, but the pressures are about 75psi on both sides of the compressor.

Early 1987 300D (sold on the lot in October of 1986)
I don't think there has ever been R134a in the system. No records of it and I am contacting the PO now.
I had it charged with Freeze 12 last year. I don't know if they also added oil when they added the freon. (I just read about the lack of a sump in the MB set up and the need to add oil when you add freon.)

My gut reaction after reading up on the forum is that the compressor siezed and crapped up the condenser and expansion valve. I think I need a flush, a new compressor, condenser, expansion valve, receiver-dryer, and new o-rings all around.

The AC guy suggested a new expansion valve to start with and try it from there.

Any ideas?

-Jim

At first thought I'm inclined to think the TXV is actually stuck open.

TXV - Thermal eXpansion Valve (aka expansion valve)?

That was what my AC guy suggested.

-Jim

OK, it wasn't the expansion valve. I changed it and the receiver dryer. It was not holding a good vacuum. (Lost 7psi in 15 minutes.) He shot soaped everything up and shot some freon to it. Everything looked great from above. From below there was oil and bubble coming from the clutch side of the compressor. Looks like I need a new compressor.

Any suggestions on where to find one? When I try to look it up it askes which engine I have:
12-023875 or the 12-023876

I have a 1987 300D. I don't have the VIN handy right now, but it was sold in October of 1986, so it is an early model.

-Jim

I just replaced the compressor on my 89 300E last weekend and I buy virtually all of my parts from The Benz Bin. I paid $342 approx. and I could store meat in the car now ! I have never gotten a bad part from the bin and just placed another order today.

I've had the best luck w/ Benz reman compressors. Some of the aftermarket bits didn't hold up well..

Just my 2!

Jonathan

Well, the good news is that your compressor is not seized. It sounds like the compressor seal is leaking. Why can't the shop just replace the seal. This used to be common failures and repairs.

Could it really be that simple? Are they the seals that are included in the o-ring kit? (Rectangular, segmented seals)

-Jim

No, those are for the head plate you have to transfer from your old compressor, and the hose connections.

Denso Compressors

http://www.densoproducts.com/resultsApp.asp?AAIA=1193802&productCategoryID=5


http://i179.photobucket.com/albums/w...compressor.gif

It's not an AC shop. It is my general mechanic, who also does AC work. I'm sure he's not comfortable cracking open a compressor.

-Jim

The seals come out the front, can be done with the compressor on the car. Common failure.

I'd check around for a Benz shop (or Toyota, it's a Nippondenso compressor) and find someone to change the seals for you, it's much cheaper than a new compressor, and likely nothing else is wrong.

however, given that there was no pressure differential and the compressor was running, it may be toast, I cannot imagine what beside a broken shaft would do that (and on a Benz, the Klima will kick out under those conditions as the speed sensor is on the tail end of the shaft).

Peter

Thanks for the info. I'll see if I can find something in any of these areas:
Huntsville, AL
Nashville, TN
Knoxville, TN

If anyone knows of a good shop in any of these areas please let me know.

-Jim