This is my opinion from personal experience and logic. Ditch the R-12. You will probably not find anyone that is licensed or willing to evacuate it. Sorta like trying to purchase a new 8 track tape or VCR. R-12 is done. Sooner or later the compressor will go, if it already hasn't, then what? You need not switch to R-134a either as it is junk in our old systems. What I have done after struggling with extreme heat in southern California desert is get rid of the converted R-134a in my system and run R-152a (Air Duster). I have posted on the site of the great success with the temps cooling way more than the 134. R-152 is plentiful, cheap (just got two 10 oz cans for less than $8.00), and you can release it freely into the atmosphere without fear of ozone depletion. Also, you can continue to use whatever oil is in your system to carry it. I am using PAG oil. I actually just bought 2 cans a few days ago because I noticed a small leak of oil at the suction line connector, I think I crushed an o-ring. But this o-ring swap will not be a $200 o-ring swap like it would be if I was running r-134. Use logic and think of the pros and cons of running the R-12 vs R-152. Good luck. PM me if you have questions for me personally about my conversion.

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1990 190E 3.0L

I have no aversion to switching to a non-tradidional refrigerant. Once I figure out if my system is functioning correctly I will definitely reach out.

The way to do that at this point is to get a set of gauges and find out what your pressures are. Since you know the compressor is actually running there's gas in the system. OR there's an electrical fault. The original problem with my SDL was a stuck KLIMA relay that let the compressor run with no refrigerant. It turned the compressor into a hunk of melted and galled aluminum.

If you convert to a new refrigerant, you've got some work in front of you. At the very minimum, a flush of the system to purge the mineral oil out and a new filter dryer. If you want to do it right, all new O-ring seals and a new expansion valve rated for R134a should be added to your list.

I've joined the list of people who don't understand the aversion to R134a. If the system is converted properly, it works fine, at least in the Gen II 126 with the small-tube condenser. My SDL cools better than my Honda does. Even on a 110˚ day, it has no problem keeping up and I have no window tint. I've run R152a and R290 (propane) and found them both to be lacking at lower speeds in the city.

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Current stable:
1995 E320 149K (Nancy)
1983 500SL 120K (SLoL)

Black Sheep:
1985 524TD 167K (TotalDumpster™)

Gone but not forgotten:
1986 300SDL (RIP)
1991 350SD
1991 560SEL
1990 560SEL
1986 500SEL Euro (Rusted to nothing at 47K!)

My plan for this weekend is to get a set of gauges, check the pressures and manually check the function of all the pods from the FSM.

Did my sight glass video confirm that there is something in the system? I have no frame of reference.

The sight glass video suggests that there's not much refrigerant in the system.

__________________
Current stable:
1995 E320 149K (Nancy)
1983 500SL 120K (SLoL)

Black Sheep:
1985 524TD 167K (TotalDumpster™)

Gone but not forgotten:
1986 300SDL (RIP)
1991 350SD
1991 560SEL
1990 560SEL
1986 500SEL Euro (Rusted to nothing at 47K!)

Actually I would just hook up the freon and fill it while watching the bubbles disappear in the sight glass. At most you might lose a can of freon.

That thing is basically empty, sub 1lb easily. BTDT on my SD.

It will take more than two, 12oz cans of R12 to fill it for good cooling...you need 46oz for a total fill (four, 12oz cans).

When was the last time it was fully charged? Are you sure R12 is actually in there?

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I'm not a doctor, but I'll have a look.

'85 300SD 245k
'87 300SDL 251k
'90 300SEL 326k

Six others from BMW, GM, and Ford.

Liberty will not descend to a people; a people must raise themselves to liberty.[/IMG]

Yes, 46 oz sounds right for a full charge. However I suspect with a can or two you can tell if it is actually going to cool.

If it does not have new connectors (like for R134A), could it have something other than freon? I have no idea. If the OP has maintenance records, that might help answer.

So I guess I agree with the NC shop who in Post #1 recommended he just try topping it up with freon. What can it hurt? You have to start someplace.

I bought it from a dinky dealer on a bring-a-trailer auction. From the carfax and the documentation that came with it, it looks as thought the PO was an elderly gentleman who owned it from new and it was only serviced it only at a MB dealership until 2 or 3 years ago. Then a couple of months ago his daughter donated the car in the san francisco area where it sold at an auction. Perhaps he passed? I dont have alot of detail, just 1-line records of bi-annual services at the dealerships. I can tell the car was very well loved but best guess it sat for 2-3 years with little use in the end. I feel strongly from my digging around that no shade tree techs have worked on this thing. It has R12 fittings.

I think that's the answer.

R12 fittings do not equal R12 in the system.

Hopefully the records will detail some work.

__________________
I'm not a doctor, but I'll have a look.

'85 300SD 245k
'87 300SDL 251k
'90 300SEL 326k

Six others from BMW, GM, and Ford.

Liberty will not descend to a people; a people must raise themselves to liberty.[/IMG]

This. My car runs 134a and still has the stock fittings. I HATE the conversion fittings, so I left it with the R12 fittings. If I ever sell the car (unlikely) I'll put conversion fittings on it.

Check the radiator bracket to see if there's a sticker somewhere saying it was converted. If a shop did it, there should be a sticker saying what kind of gas they put in it.

__________________
Current stable:
1995 E320 149K (Nancy)
1983 500SL 120K (SLoL)

Black Sheep:
1985 524TD 167K (TotalDumpster™)

Gone but not forgotten:
1986 300SDL (RIP)
1991 350SD
1991 560SEL
1990 560SEL
1986 500SEL Euro (Rusted to nothing at 47K!)

Untitled by ttownthomas, on Flickr

Pulled the monovalve today. The seal was torn. I assume this is part of the problem and that this is allowing coolant to bleed into the heater core during "max cool" and other various cooling operations.

Gauges arrive tomorrow.

I don’t know why so many people act like r12 is gold and not obtainable. It’s easily purchased on eBay. Buy a few cans and recharge your car. If it leaks out again, find the leak, fix it, and recharge your car by weight.

I’ve done the r134 conversion and it’s ok at speed, but is useless in traffic. I don’t have much experience with drop in substitutes but generally more of a hassle than it’s worth.

__________________
Eugene

10 E63 AMG
93 300te 4matic
07 BMW X3
14 Ford F-150 Fx2

You need a license to buy R12, even from ebay.

My 1991 300se has envirosafe es12 in it, installed by the previous owner, and it seems to work well. Not as good as r12 but better than r134. I had r152 from canned air in my 1979 300d, it worked well too except when sitting in traffic for long periods of time.

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"It's what non-car people don't get. They see all cars as just ton-and-a-half, two tons of wires, glass, metal and rubber. That's all they see. People like you or I know, we have an unshakable belief that cars are living entities..... You can develop a relationship with a car, and that’s just what non-car people don't get."
-Jeremy Clarkson