After years of owning a W123 Euro with factory aircon, the equipped Harrison H4 (Delco) compressor breathed its last a couple years ago. Rather than risk another failure, I reached out to Klima, who shipped me a Sanden compressor and kit.

- All hoses were replaced.
- I had already installed a new condensing radiator (Behr).
- New Receiver dry installed
- Gas pressure holds constant (no leaks)

The aircon works but it is nowhere near as capable of lowering grill temperature (recorded at 16 degrees C with the old compressor on R24 gas before it died).

Is this normal when switching gas type? OR have I missed something?

TIA!

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Why I will never do business with "DieselKraut" again

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This.

I assume you’re now charged with R134a? Your performance will be lackluster with the original serpentine condenser.

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79 300TD “Old Smokey” AKA “The Mistake” (SOLD)
82 240D stick shift 335k miles (SOLD)
82 300SD 300k miles
85 300D Turbodiesel 170k miles
97 C280 147k miles

Definitely an OEM condenser. Would it make sense to ditch R134 and go back to R24 gas?

It's more expensive but is still available and I believe the Sanden compressor will take it.

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Why I will never do business with "DieselKraut" again

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There is something else going on. I have a factory condenser on several 123's running 134. They work fine as long as you are moving. The parallel flow condenser on my 84 only really shines at idle.
What are your pressures?

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1985 300 TD 448K
1984 300 TD 278K

1983 240D euro 240k
1994 f-250 idi turbo 330K
1986 f-350 IDI
1987 F-350 IDI

1985 JD 1050 4wd
1965 IH 3660

I installed a full Klima Design kit on my 85 TD; all new hoses, dryer, expansion valve and including his parallel flow condenser and larger electric fan. I am running R12 rather than R134 because I had quite a few old cans stockpiled. According to Matt at Klima, R12 will improve cooling performance a bit over R134 and will not leak out as easily due to larger molecule size. I am not familiar with R24. My system cools very nicely especially after performing one important, but time consuming job... pulling the dash, removing the evaporator from it's box and cleaning out the years of accumulated crud in the fins. At least 1/3 of the evaporator was completely plugged with fibers and debris. The 123 has no cabin filter so any floating particles can get sucked into the evap fins. Also keep in mind to check compressor oil requirement for the type of refrigerant you are using. I had to flush my Sanden and use R12 compatible oil. I would have used R134 had I not had the R12, I am confident the system would still perform satisfactorily. Good luck!

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Owner of Mobil-Werks
Classic Sports and Specialty Automobile Service
1968 230 W110 +3.5 M116 & 4-Speed Manual
1985 300TDT S123
1985 500SEC C126
2022 Sprinter 3500

Think of R24 as a version of R12 that is still sold (atleast here in the UK). You described the one thing I have not renewed on the car - the evaporator. I'm not sure mine would have as much crud in it given the extremely low use but it is something I suppose I would need to cross off the list to be sure...

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Why I will never do business with "DieselKraut" again

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Remember air blows through the evaporator anytime the blower is on so its "use" is not related to having the ac on.
You can drop the blower and use a smartphone to take pictures of the evaporator and get a good idea of how clogged it is. You can also clean it pretty well with the spray coil cleaners from that same spot without pulling the dash.

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1985 300 TD 448K
1984 300 TD 278K

1983 240D euro 240k
1994 f-250 idi turbo 330K
1986 f-350 IDI
1987 F-350 IDI

1985 JD 1050 4wd
1965 IH 3660

If the evaporator is clogged, air temps will be lower, but airflow is reduced, limiting cooling in the cabin.

If you are experiencing cool air, stron airflow, but not much comfort in the car, an it is below 92F upside, AND the car is in motion, most likely, the system is overcharged. Have a shop remove a few oz from the charge, you don’t want the suction pressure to be above 38psi at idle…

I will add my vote to installing a micro channel condenser… at least a booster add on coil. 134 just doesn’t have the heat capacity of R12…

If R24 is a blend hc refrigerant, id go back to that.

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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!

The reason I suspect the evaporator is fine is simply this: Before the H4 compressor died, 3 years ago, the grill temperature was freezing cold. I think it measured 15.5 degrees C. It was running on R24 refrigerant.

We are experiencing cool but not cold air, strong airflow, but not much comfort in the car at or above 92F outside, while the car is in motion.

Point taken on the condensing radiator.

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Why I will never do business with "DieselKraut" again

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Can't remember where I read it; a MB owner said his Klima monovalve replacement kit didn't like to play well with the climate control head. Anyone have more knowledge about this issue?

Sanden + PF condenser + R12. That is the dream system. People here have also had great results with the isobutane blends.

I like the idea that the R12 runs at a lower pressure. R134a in my R4 compressor has killed my mpg and what little power my little 617 turbos make. The higher pressure is just an uphill fight because you switch to barrier hose and put more pressure on our 40 yo evaporators. And after all that you get less cooling power.

The decision to switch refrigerants and/or condensers is up to you. Both/either will give you lower vent temps. Each one has different work that needs to be done. Your system is full of PAG oil now. Going back means flushing and adding mineral oil. Or a new condenser requires some fitting (if you buy a universal) and some custom hoses. Klima can set you up but you have to pay for their plug and play convenience.

I went with a new pf condenser when I was at your juncture. I didn’t want to deal with sourcing R12 and it would have been a disaster given how many times I’ve torn my system down and recharged while I’ve tinkered with it.

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79 300TD “Old Smokey” AKA “The Mistake” (SOLD)
82 240D stick shift 335k miles (SOLD)
82 300SD 300k miles
85 300D Turbodiesel 170k miles
97 C280 147k miles

You'll need a parallel flow condensor to truly get better performance out of the Sanden and R134a.

My experience with a Sanden on my 1985 300D. It didn't cool any better, with same refrigerant. I went back to an R-4 after Rollguy's bracket cracked several places. Cools OK, even in our sunny 100F days, as long as car is moving. Same in our 2002 Chrysler, when stopped the AC gets noticeably warmer.

Idle.

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79 300TD “Old Smokey” AKA “The Mistake” (SOLD)
82 240D stick shift 335k miles (SOLD)
82 300SD 300k miles
85 300D Turbodiesel 170k miles
97 C280 147k miles

Now you're getting the idea ! .

Hopefully an image at 3,000 =/- RPM is coming soon .

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-Nate
1982 240D 408,XXX miles
Ignorance is the mother of suspicion and fear is the father

I did then what I knew how to do ~ now that I know better I do better