AC Trouble in 83 300D

[rfdillon]

Folks, a couple of weeks ago I drove home on a Monday evening, and had cold AC when I shut off the engine. The next morning I fired up the car to go to work, and no AC!
I took it to the shop, who tells me that there is a blockage somewhere in the AC system, and that the compressor is making a bunch of noise. I'm not real sure they know what they're talking about, as they don't work on many old Benzes, but does anyone have any suggestions as to where they should start? Also, if I need to purchase an expansion valve, or new AC compressor, from where would I find these parts at the best price?

Thanks so much in advance for your help!

[Whiskeydan]

Blockage??? In the flow of freon or air blowing across the evaporator?

Is the compressor clutch engaging?

[JimmyL]

Originally Posted by rfdillon

Also, if I need to purchase an expansion valve, or new AC compressor, from where would I find these parts at the best price?

We are only allowed to recommend getting parts from the site here. {at the buy parts tab above}
It sure ain't the best price, but very good service.

Did they mention what the pressures were doing? Sometimes the monovalve can go out and overpower the AC system with heat. However, if they are saying you have a blockage then hopefully they have determined that with high and low side pressure readings.
Other than the quirky monovalve, these are very straightforward and "normal" AC systems. {not including the Climate Control module of course. [push button thingy]}

[zeke]

Originally Posted by JimmyL

We are only allowed to recommend getting parts from the site here. {at the buy parts tab above

Except Fastlane does not stock the compressor. So we can tell you that Fastlane lists the compressor, but many other outlets actually have it available.

Also, I will note that this is a GM compressor used in MANY American made cars during the 80's and 90's. Sooooo......if you find some boys with pep or some sort of zone for autos that stock parts for american cars, you could be in luck.

I think Fastlane does stock the expansion valve.

[rrgrassi]

I bought a NEW Hodyon (Hancock Ind) R-4 through NAPA. Price was $250. It has lasted past it's warranty so far. The rebuilt Murray I installed prior to the new one, lasted one day past it's warranty. The clutch/pulley bearings failed.

The new compressor is not noisy. I can tell it's engaged by the power difference in acceleration.

If you do get a new compressor, replace the expansion valve and drier as well.

I'm not going to tell you which refrigerant to get. I will say to avoid r-134 unless you live in Canada.

[rfdillon]

Thanks so much, folks, for your recommendations. I haven't heard back from the mechanic for a couple of days, and I don't have a warm fuzzy that they know what they're doing. By the way, I'm using Freeze 12 as a refrigerant - it works great in R-12 systems. By the way, if I should run into a peppy zone somewhere, what is the precise model of compressor that I should ask for?

[zeke]

Originally Posted by rrgrassi

R-4

[rfdillon]

Thanks again, folks for all your helkp. It turned out that the drier was completely plugged up with metal particles - I guess the compressor had been going out although still working. After the AC stopped blowing cold, the compressor made a lot of noise, so I'm replacing it and the drier and the expansion valve. I'll let you know how things go!

[rrgrassi]

Make sure you flush the entire system to get rid of all the metal particles. Get the NEW R-4 made by Hodyon (Hancock Ind). I am using Freeze-12 also, and it works for me. Freeze-12 does use the ester type oil that R-134 uses, and since Freeze-12 is a blend, it makes sense. Get the BG Frigiquite oil. If you can't find it, get the GM rated ester oil. It's a bit thicker and designed for GM systems. The R-4 is a GM designed compressor.