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Climate Control:
http://www.peachparts.com/shopforum/showthread.php?t=142408

All refrigerants are chemical concoctions. A blend means that it is an azetropic mixture and is the way to get the desired properties of a specific refrigerant and engineer out what you dont want. As long as you are not using an "near azertropic" mixture which will experience fracternization if introduced in the system as a vapor. They must always be charged as a liquid.

Using what many keep saying is a "blend" if it was used in the application for which it was engineered. Freeze 12 was engineered with modern technology to do just what R-12 does but with lower pressures. Same idea with R-410a replacing R-22, except you must use different equipment to handle the almost 100% increase in pressure with R-410a.

What most people dont understand about refrigeration is that it all works basically the same. I could run R22 in the MB and get it just as cool if I changed out different components. Point is that Freeze 12 is designed to work in place with R-12 with better performance. Don't listen to all the "sky is falling" types out there.

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1981 300D 147k
1998 VW Jetta Tdi 320k
2001 Dodge Ram 2500 141k
1979 300D 234k (sold)
1984 300D "Astor" 262k(sold)
Mercedes How-To and Repair Pictorials
I love the smell of diesel smoke in my hair

Refrigerants have R DESIGNATIONS...
When I say BLEND ( or the EPA calls something a BLEND)... it means more than one of those are put together..
FREEZE12 is 134a PLUS one of the R400's.

What it means in a practical sense is that since AC shops are typically set up for EITHER R12 OR R134a ...
and are very careful about mixing refrigerants in there equipment due to the different oils used ...and other considerations..

You are not likely to find a shop who will service your BLEND equipted system...

Don't take my word on this... call around your local area saying you have FREEZE12 in your system and need it topped off or checked or serviced...

this is in addition to having to load in the liquid state ( which if the valve on the downside of your compressor is faulty can break reed valves just like mistakenly putting liquid into the suction side, having to worry that leaks will allow only the lightest element out ( which may be the better oil carrying one ).. , and there is the oil miscibility question .. which everyone agrees is not a problem with R12...

Oh-h.. black death! I'd read about it before, but had forgotten. It's generally reversible with some work, though, isn't it? Our condensers are tube-and-fin, and thus easier to flush than newer parallel flow or multi-pass types in the event of black death -- yeah?

Not that I'm going to risk it.

I'm figuring up a budget on doing a total overhaul right now, as opposed than getting a top off at a shop and allaying the overhaul until autumn marathon garage sessions. Currently stuck at the o-rings; as I'll be removing the compressor, how many of each type of o-ring do I need?

It is not reversible FOR THAT PARTICULAR COMPRESSOR... it means that one bit the dust and spread its guts into the system...
The other parts of the system are cleanable .

However, I will mention here at this point in the discussion that the MB Factory Shop manual says that in case of black death the PIPE MANIFOLD which connects to your Delco must be replaced due to having filters in it which may not be able to be cleaned... few if any people do this.. but the manual says to do it... finding a new one would be a pain.. but I guess it also means if you cleaned one from a car which had a good compressor that would be ok ( assuming no time in history of car black death ever occured )....

I do not think it is the type of design with regards to ' tube and fin'... but the size of the passages which make the old ones easy to flush effectively.

I believe that the Oring set for our cars is available as a packet from Carlisle Auto Air in San Antonio.... I think the part number is 100... but I have posted that in the archives....

The original Delco had actual orings.. but the discussion going on currently says it no longer does..and they give the Napa numbers there..

I had many a 2002 and none of them ever had the factory air and I lived in Florida. Now I am 20 years older, living in New York and have a 1985 300TDt and I want to fix my AC so I too can stay cool. Seeing this thread gets me going. I always wanted to do my own AC work and maybe this summer is the time. My wife's car AC works but not super well. I want to diagnose it and get it working better.

Thanks John.

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Doug

1987 300TD x 3
2005 E320CDI

Is there a way to tell if the oil is present in the compressor at satisfactory level?! Is there a 'minimum' a guy should check on the system before recharging the Feon (134a), or do I have to work my way through the entire system to avoid problems?! Seems like a lot for me right now...

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1987 Mercedes 300SDL; SOLD
1985 Mercedes 300D; SOLD
2006 Honda Pilot - wife's ride; 122K;
1995 Toyota Land Cruiser - 3X locked; 182K

This is a huge problem for everyone... you are not alone....all the pros are in the same boat... if you have a leak .. it is assumed that oil was taken with it... if you have the Delco compressor it does not even have a sump like the old York... so all the lubrication which it gets is from it being dissolved in the Refrigerant and moved around the system...
The only way to know for sure on a system new to you is to flush ( and replace the usual things ) and measure the amount of oil into it.... same with the refrigerant.
Since the oil amount is very important.. not only on the low side.. but too much is very bad also... and will overwork your compressor and adversely affect you cooling in short order.. thus you can not just add oil to be on the ' safe ' side...
It is a bummer of a situation all around... but done right a system has the potential of lasting a long time with no further problems...

Mine's got the Frigi-King, but it's been non-op since long before we met. I mean to take it out, but haven't gotten around to it; my parts car has even got a good original radio center console. Still searching for that manual Webasto, though!

When you get down to it, this A/C work, is really surprisingly simple.

1. Remove compressor, drier and expansion valve
2. Flush system (aerosol or standard)
3. Fill compressor and drier with oil
4. Install compressor, new drier and new expansion valve using new o-rings
5. Prime compressor by hand (or applying direct current) to circulate new oil
6. Pull vacuum to remove all moisture (60 minutes)
7. Start engine, crank A/C to high and fill with refrigerant

Topping-up, however, is another story.

This oil thing is a major hitch, isn't it? I'm all but set to succumb to decadence -- or should that be "avoid masochism" -- and let this A/C garage do a blind recharge (still waiting for my 609 hard copy to come thru the mail, and the tiny local shop with the lowest R-12 price refuses the temporary certificate), but the whole time the oil issue's been lurking in the back of my mind. I read in the Climate Control Manual that with the York compressor, the minimum oil level is 180cc, the normal 240cc and maximum 300cc. So, could one figure that in a system the history of which isn't known, figuring using statistics that it's a slow leak, it'd be safe enough to inject 60cc with a full recharge -- if only to appease one's neuroses? I mean, reading the math, would this make it any more likely that the compressor might fail due to over-oiling?

It's all moot anyway, as I and most of us have got Delcos. In the Delco section the manual reads:
It actually addresses the situation specifically! The question is, should one put in 30cc (1oz), or 90cc, which the manual seems to indicate as the golden number?

Of course, in the end, anything but an overhaul is guesswork.

It sounds like the systems are so sensitive to any moisture and dirt that messing with a nonfunctioning system that may have taken on moisture from a leak is just not worth it. I have a friend who has the vacuum pump to draw the system down once I have replaced eveything. I think I will finally invest in a manifold and set of gauges and give it a try myself.

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Doug

1987 300TD x 3
2005 E320CDI

If this guy sounds like a salesman, it is because he sells Freeze 12 on his website. What would you expect him to say?

If your system has the smallest leak, any leak at all, Freeze 12 will separate and lightest part of it will leak first. Then you cannot "top off" your system to regain the lost performance, you have to purge it and start with a fresh charge.

So if you save a buck this year you lose it back when you need to "top off" the system.

Listen to the guys that aren't after your money.

What I've learned from all the reading and research I've done on this is that hands down the best way to go is to simply get the 609, use an afternoon to overhaul the system and charge with R-12.

I've come to feel that when it comes to refrigerants, performance and cost aren't issues: our A/C systems are more than effective using the refrigerant they were designed around (which is readily available at even large chain parts stores, at a premium), and with a fully refurbished system, the R-12 (while comparatively expensive) won't need a recharge for ages, if ever.

I'm putting in orders for a new expansion valve, drier and o-rings, and will try for some R-12 via eBay as I wait for delivery. Once everything's together, probably about three weeks, I mean to thoroughly photograph the entire overhaul and compile us a definitive MercedesShop DIY A/C Guide.