Well my beloved little 240 is not blowing ice cold anymore. The old R12 system has not been touched since it was new in 1979. Everything still works, it's just not getting ice cold anymore. The site glass on the RD is still showing freon/oil going thru but it's apparent it's short of freon a bit.

So, my indy says he still has gauges for R12 but doesn't have any on hand. It's pretty easy to come by here in southern Cal, plenty of NOS cans from private sellers on craigs. 3 cans are $75 to$100. But my guy doesn't want to mess with them, he wants to convert it to R134.

He says evacuate it, replace RD, and then charge with ester oil and 134, hard-wire the fan on with the comressor. He wants like $600 to do this. And yeah, it may toast my compressor but then at least it's easy to replace it with a 134 style unit and set it up again.

What would you old pros suggest?

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Chris Brown
"OC", So-Cal
1979 240D, 122K, 4spd, Colorado Biege w/Tobacco, Pwr Roof, AC, Cruise, Becker Corona - SOLD
Past Benzos: 71 250 • 83 240D • 84 190E • 04 C240 • 11 GLK350 • 13 c250 Coupe
http://www.peachparts.com/shopforum/...ine=1276896801

Roll the window down, and open the sunroof......

If there is still r12 in the system, find another ac shop to take it too.....tell them it needs a charge.....

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Seems Rollguy is a AC guru of sorts and he's local to me. Have PM'd him, perhaps he can help me with it.
I'd rather buy a set of gauges and a pump and do it myself. Freon is easy to come by here, there must be a half dozen ads in craigs, all NOS cans of it.

__________________
Chris Brown
"OC", So-Cal
1979 240D, 122K, 4spd, Colorado Biege w/Tobacco, Pwr Roof, AC, Cruise, Becker Corona - SOLD
Past Benzos: 71 250 • 83 240D • 84 190E • 04 C240 • 11 GLK350 • 13 c250 Coupe
http://www.peachparts.com/shopforum/...ine=1276896801

That's what I ended up doing, but my car was already on the 134 diet so I filled it with envirosafe.

$600 is steep too. I replaced the DR, compressor, and expansion valve for less than that. I also bought the tools needed for less. haha

Agreed and you if you find a good shop, you can have them vacuum the system dry, take it home....replace everything yourself....then take it back in to have vacuum, tested and filled...

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Yeah, I had a shop recover the old refrigerant. They didn't charge me. But I bought a vacuum from harbor freight for pulling a vacuum for recharge.

I am curious how a closed system can lose freon gas unless it had a leak?

__________________
1979 300D 220 K miles
1995 C280 109 K miles
1992 Cadillac Eldorado Touring Coupe 57K miles SOLD
********************
1979 240D 140Kmiles (bought for parents) *SOLD.
SAN FRANCISCO/(*San Diego)
1989 300SE 148 K miles *SOLD

Most likely there is a small leak, through rubber hoses.

Potential leak points I can think of off the top of my head:
- Hoses (they are inherently porous, before the days of R134A they did not have an impervious barrier inside, and can also develop cracks from age)
- O-rings at hose joints
- Seals in compressor, especially shaft seal and the housing seal on an R4
- Crack in tubing on condenser or evaporator, from fatigue, accident damage, corrosion
- Crack in rigid line from fatigue, improper securement causes flex or rubbing

Also do an advanced search for R12 and user Vstech, unfortunately he lives in NC, but he is the man when it comes to air conditioning.

__________________
The OM 642/722.9 powered family
Still going strong
2014 ML350 Bluetec (wife's DD)
2013 E350 Bluetec (my DD)

both my kids cars went to junkyard in 2023
2008 ML320 CDI (Older son’s DD) fatal transmission failure, water soaked/fried rear SAM, numerous other issues, just too far gone to save (165k miles)
2008 E320 Bluetec (Younger son's DD) injector failed open and diluted oil with diesel, spun main bearings (240k miles)

1998 E300DT sold to TimFreeh
1987 300TD sold to vstech

Good to know.

I just remembered hearing from a friend that condensers, in general, have leak problems due to vibration over time.

Thanks.

__________________
1979 300D 220 K miles
1995 C280 109 K miles
1992 Cadillac Eldorado Touring Coupe 57K miles SOLD
********************
1979 240D 140Kmiles (bought for parents) *SOLD.
SAN FRANCISCO/(*San Diego)
1989 300SE 148 K miles *SOLD

I'd convert it to 134a. You can do it yourself if you have access to a vacuum pump and manifold gauge set. Even if you have to buy the vacuum pump and gauge set, you'll almost certainly still be under the mechanic's quote of $600.

A friend and I have converted about ten cars, many of them Benzes, to 134a. A few of them are coming up on three years of use and I have yet to see a single compressor fail as a result of the conversion.

These cars, especially the ones with the Sanden/Denso style compressors, blow very cold air when converted properly. I have put IR thermometers on the air vents and seen temps as low as 34 degrees F.

It's not as complicated as others would like you to believe. Remove the fittings under the hood and replace the O-rings with 134a compatible parts. If you would like, you can remove the compressor and drain it of its oil. (I don't always bother to do that step- if I don't, I just vacuum the system longer). Replace the receiver dryer (the little cylinder in front of driver side fender next to the radiator) and if you don't mind spending the extra $30, replace the pressure switch on the dryer. Vacuum the system down for a long time - 3-4 hours - to completely boil it out. This is where you can check for leaks- the system should hold vacuum for a long time; needle shouldn't drop. If it does, you need to find the leak. If it's solid... charge the system with Ester oil and 80% of the printed R12 capacity.

Total parts investment is under $100 and you'll have ice cold A/C for years to come.

The metal hoses connected to my compressor cracked right after I had spend money to get the rubber on it replaced. I was so pissed.

I wish I would have researched it more before buying a compressor and gotten and Sanden.

Seems easy enough.
This is what my indy was going to do and charge me $500 plus a hundred to wire the condenser fan to stay on with the compressor. I'm thinking I can do that as well if it's suggested.

__________________
Chris Brown
"OC", So-Cal
1979 240D, 122K, 4spd, Colorado Biege w/Tobacco, Pwr Roof, AC, Cruise, Becker Corona - SOLD
Past Benzos: 71 250 • 83 240D • 84 190E • 04 C240 • 11 GLK350 • 13 c250 Coupe
http://www.peachparts.com/shopforum/...ine=1276896801

I would not recommend converting it. Just find a shop with R12 or do it yourself. You WILL NOT get the same performance from 134. I have an 84 300D that is on 134, the second something goes wrong with the system I am going to re-convert it back to R12.

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2001 G500 (45k and counting)
1991 350SDL (211 and counting)
1998 C43 (50k) Silver/Black (sold)
1995 E500 (40k and counting) Pearl Black/Anthracite (sold)
1991 300CE (50k and counting) Silver/Black Cloth (sold)
1983 300D - 79k Classic White/Blue Leather
2002 E55 Obsidian Black/Black
1996 S600 Coupe - 75k Black/Black (traded)
1984 300D -145k (sold)
Silver Blue Metallic/ Blue Leather
1985 300D - 87k (sold)
Manganese Brown/ Palomino Leather
2005 E55, 50k(sold)
Flint Gray/Black

before going to the work of converting it, or even adding R12, I'd pull the aux fan, and radiator, and clean the gunk from the coils, and soak the condenser with coil cleaner, and get all the fins bright. you might be low, you might just be dirty.
it's a LOT of work to clean stuff, but it's WELL worth it.
then I'd verify the aux fan is coming on. you may just have a bad aux fan.
is your compressor the old YORK clunker on the passenger's side, or the R4 compressor under the power steering pump?

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John HAUL AWAY, OR CRUSHED CARS!!! HELP ME keep the cars out of the crusher! A/C Thread
"as I ride with my a/c on... I have fond memories of sweaty oily saturdays and spewing R12 into the air. THANKS for all you do!

My drivers:
1987 190D 2.5Turbo
1987 190D 2.5Turbo
1987 190D 2.5-5SPEED!!!

1987 300TD
1987 300TD
1994GMC 2500 6.5Turbo truck... I had to put the ladder somewhere!