My system is tight. I had replaced compressor 3 years ago and been fine on 134A. No leaks and so so cool. I had put in ester oil so I could go back to R12.

How much better cooling should I get? worth the effort and cost??

__________________
1982 300SD

Long answer is how deep is your pocket, how much time you have and how competent are you? You have to do it yourself, may be with moral support from this forum as NO shops will touch R12.

Short answer is NO.

There is a post recently on a successful R134 system and all my cars are on 134 with great cooling.

__________________
Not MBZ nor A/C trained professional but a die-hard DIY and green engineer. Use the info at your own peril. Picked up 2 Infractions because of disagreements. NOW reversed.

W124 Keyless remote, PM for details. http://www.peachparts.com/shopforum/mercedes-used-parts-sale-wanted/334620-fs-w124-chasis-keyless-remote-%2450-shipped.html

1 X 2006 CDI
1 x 87 300SDL
1 x 87 300D
1 x 87 300TDT wagon
1 x 83 300D
1 x 84 190D ( 5 sp ) - All R134 converted + keyless entry.

Yea, in San Diego!!!

I use alternate freons as much as anybody, but still R12 gives you the BEST shot at cooling. Sure, in some climates R134a works just as well, but when you climb into the 90's and above it just won't give you quite as much.
If you have some R12 I would certainly use that over R134a.....

__________________
Jimmy L.
'05 Acura TL 6MT
2001 ML430 My Spare

Gone:
'95 E300 188K "Batmobile" Texas Unfriendly Black
'85 300TD 235K "The Wagon" Texas Friendly White
'80 240D 154K "China" Scar engine installed
'81 300TD 240K "Smash"
'80 240D 230K "The Squash"
'81 240D 293K"Scar" Rear ended harder than Elton John

If your car is in decent shape, and your AC system holds pressure well, it may be worthwhile to go back to R12.
I have a pair of 240ds. One had a quickee R134 conversion kit some years ago, and compressor noise & engine load are higher than normal, while cooling on 90+ days is mediocre (though better than nothing) There is a slow leak in that AC and the car is a rustbucket, so no way would I waste my precious R12 on it.

OTOH, I have a really nice 240D, with a replacement compressor, so I gambled some R12 on it and it's been holding pressure for over a year, and system performance is so much better than the AC in the rustbucket.
Now perhaps if I replaced the compressor in the other car, it might perform better with R134, but that car just isn't worth it.

Happy Motoring, Mark

__________________
DrDKW

Instead of switching ...
first try cleaning your evaporator fins...
thread by DMorrison shows how bad it can restrict flow... and insulate the unit from the air which needs to be in contact as it passes through...
THEN if that does not really help... think about the other things...

__________________
1980 240d ,

chain elongation, cam marks reference:
http://www.peachparts.com/shopforum/diesel-discussion/10414-help-i-need-check-stretch.html

http://www.peachparts.com/shopforum/diesel-discussion/305365-9-degrees-chain-stretch.html

evap fin cleaning:

http://www.peachparts.com/shopforum/diesel-discussion/156207-photo-step-step-post-showing-w123-evaporator-removal-1983-240d-1982-300td.html?highlight=evaporator

A/C thread

http://www.peachparts.com/shopforum/diesel-discussion/297462-c-recommendations-mb-vehicles.html

The SD (W126) evaporator is somewhat accessable for cleaning if you pull the blower motor ass'y. I've flushed 'em this way with a water hose which drains via the condensate hose. Have a wet vac and some towels handy for the overflow spills.

You can get very good performance with R134 if you install a >'85 condensor in the W126.

My shop has no problem working with R-12, and it works better than 134a in old systems. There is no reason not to use R-12, that's what the system is designed for. I tried r-134a, I didn't like the performance and converted back to R-12.

here's another vote to switch back to R12.

Every auto shop I know of around here deals with r12. Local NAPA stocks r12.

__________________
1998 E300 +310,000K
1996 E300 +460,000K

Here in Central Florida it is freaking HOT!!! The system in my 1985 300d rebuilt with 134a is cool at best! Brand new compressor, Dryer, & wired the electric aux fan to come on when the ac is on. It blows maybe 52 right at the vent. plain and simply not enough to ride comfortably in heat indexes of 100 degrees! AND I have my windows tinted BLACK to fight off the heat rays!
If I can get cooler results switching back to R12 then I'm gonna look into it too!!
I cleaned my evap fins in my other 300d with little to no change in actual results, but may look at doing this one just for grins. It was a easy thing to do and cleaning that crap out from 25yrs of use surely could not hurt!!

(Keep in mind that right now my car has no AC coming from the center vents due to vacuum element being defective but that will be repaired this month!)

What are we talking price wise for the reconversion? 3 cans of R12 and some oil and maybe a charge to the mechanic to vac....$200 total?
If it will give me 10degrees cooler it would be WAY worth it!!!!!

__________________

2006 Jetta TDI DSG 320k miles
1997 Ford F150 325k miles 4.2L V6 "Work Truck"
2008 Tundra 225k miles 5.7L
1982 240D.....sold
1984 300D...Totaled OUCH!
1985 300D Turbo 222k miles "Dos" sold to 79Mercy
1986 300SDL 98K miles "The Beater"....sold
1987 190E 2.3 16v Euro spec 115K miles....sold

It really depends on the condition of the rest of the system. I'm in North Dallas and have a 450SEL 6.9 that cools great with R134. I had a 560SEC which I personally charged with R12 and it was great until the temps went over 100 degrees , then it was 'eh' at best.

But going back to your question. So you used R134 and ester oil and you want to go back. Then all you have to do is pay someone to pull a vac and recover the system (about $30-$50 at most oil change places) and then charge up with R12.

Can's go for about $20-$25 each and you'll probably need 3-4 cans. So $100-$150 if that's all that you're doing.

__________________
With best regards

Al

One of my favorite Texas sayings describes that situation perfectly: "All hat, no cattle."

first, your 85 should be doing better than 52 at the vent. (not much better mind you, but better than 52..) all the things you have done to the car are good, but you forgo the most important part of removing heat from the car.
the condenser.
it must be clean also.
remove the radiator (heck, do a cooling flush while it's out.) soak the condenser with cleaner from the back. get it VERY coated with degreaser, and bug dissolver and soak the daylights out of it. keep soaking it until you are certain all gunk is dissolved. and rinse it from the back. strong but don't bend any fins.
another thing you could do is get some commercial coil cleaner and soak it in that. pricey at $15 a gallon, but it will get the aluminum fins and coils cleaner than any other cleaner.

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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 560SL convertible
1987 190D 2.5-5SPEED!!!

1987 300TD
2005 Dodge Sprinter 2500 158"WB
1994GMC 2500 6.5Turbo truck... I had to put the ladder somewhere!

You puriists can stay with R12 for all I care.

I am only stating the obvious. If you can find a shop for the OP to restore it back for cheap then it is fine. Remember, all you can offer is advice or moral supports unless you offer wrenching help. Talk is cheap. May be you A/C experts can pick up a wrench and help.

__________________
Not MBZ nor A/C trained professional but a die-hard DIY and green engineer. Use the info at your own peril. Picked up 2 Infractions because of disagreements. NOW reversed.

W124 Keyless remote, PM for details. http://www.peachparts.com/shopforum/mercedes-used-parts-sale-wanted/334620-fs-w124-chasis-keyless-remote-%2450-shipped.html

1 X 2006 CDI
1 x 87 300SDL
1 x 87 300D
1 x 87 300TDT wagon
1 x 83 300D
1 x 84 190D ( 5 sp ) - All R134 converted + keyless entry.

You are obviously misinformed and mistaken.

I can assure you that not everyone shares your fascination with "cheap." The OP already tried "cheap" and has now discovered that it didn't work out very well.

Absolute rubbish.

Bad advice isn't.