1982 300CD W123, much improved air conditioning!! Klima parallel flow condenser
 

I had one of these parallel flow condensers from Klima installed. Greatly improved Air conditioning! Prior to this, the AC wouldn't work well in stop and go driving on a hot day. Now, it works well in all hot conditions. Don't forget about the new expansion valve.

https://klimakit.com/product/parallel-flow-condenser-upgrade-kit-w123-2/

https://klimakit.com/product/thermal-expansion-valve/

Hey, that's awesome! Great news. Nothing like a properly functioning ac system....on a car, or anything else. Truly, one of man's great inventions!
What about your compressor? Original, or had you already replaced that previously? Filter/dryer? It gets a little pricey, but the end result is well worth it in my book.
Air conditioning used to be considered a luxury. In my opinion, it still is. And, luxuries cost money. It's just more commonplace, these days, and "built in" to the cost of new cars. Considering the cost of new and used vehicles now, it's a luxury alright. Cheers!

My existing A/C compressor was working well. For me A/C is a necessity since I use my 300CDs as daily drivers.

Klima offers good kitted solutions, though pricey. I have bought parallel-flow aluminum condensers for my 1960's Mopars for $50. Klima's gives you the proper M-B fittings and attachment brackets, but for $260. If re-hosing, might be preferable to change to more standard O-ring tube fittings, which I recall are #8 on the inlet and #6 on the outlet (liquid line) and use a cheaper, commoner condenser.

Re compressors, I had a Sanden on my 1984 300D for around a year, until Rollguy's custom bracket cracked, so went back to an R-4. Both cool about the same, which is "not good" when sitting at a long stop light. But, our 2002 Chrysler 3.8L is similar and it has 2 more powerful electric fans (no mechanical fan). Once moving about 30 mph, both vehicles blow cold air.

Exact same here. Did the Sanden. Vent temps didn't drop until the PF condenser was installed. If you have a working R4 system I'd leave the compressor alone and just change the condenser. If you're willing to bend the brackets on the stock condenser it can come out through the front. I did the whole thing with the radiator just tilted back with the top 2 clips removed. Their PF condenser saves a lot of R&D/prefab work on removable brackets, matching the stock mounting points, and plumbing the hard lines into the engine bay. I did add Loctite to each bracket screw.

I was wondering when the AC threads would start showing up this summer:D

my last w123 ( red 4 door ) had ice cold AC with stock r4 and condensor weird as i'm in australia :/

I just hope when i get my latest w123's AC sorted it's just as good.

do the later w123's have a different condensor ? the ( red 4 door ) was a 1982 and my new w123 is a white coupe from 1985 if that makes a difference

Math, I'm pretty sure they all had the same condenser.

Y'all use hydrocarbon refrigerants down under do you not?

I use HC refrigerant (Duracool) in 6 of my 7 vehicles. It works slightly better than R-12 and much better than R-134A. I understand it has long been popular in Canada, where my bottles have shipped from. I did hear of an Aussie story where an AC tech there purposely staged a fire with HC refrigerant to "prove" how dangerous it is. It isn't, indeed that is the only fire I've heard reported in millions of cars using it.

A few years ago I tried an experiment. I added a second auxiliary fan to the condenser. I thought this might help. I can't say that I noticed a difference. It was a nice try though.

http://www.peachparts.com/shopforum/...17-aux-fan.jpg

It would only help if you going less then 15mph
cleaning those fins would help more.

There also used to be a video circulating of a Porsche 924/928 club one of whose members had an overly long refrigerant hose severed by a fan blade which then came to function as an underhood flame thrower.

I find that the hydrocarbon works well at speed, not that well when idling. It certainly beats 134 which in addition to not cooling well also destroys compressors on the regular.

R134a Operating Pressure
 

Greg ;

What is the low side pressure you're using ? .

My '82 240D has one of Rich's SANDEN / PF condenser mods, it used to blow ice cold, then after a year or so tapered off to maybe 70* F at the dash center vent .

I stopped doing AC repairs when this was a new car so I'm a bit rusty .

Yesterday I bought one of those $35 18Oz recharge cans with a low side gauge on it and discovered my system only had 15# in it, I slowly added R134a with the windows open and the AC blower on high, when I reached 34# I stopped and buttoned it up, took a test drive :

At freeway speeds I now get 58* F at the dash, when I stop for a traffic light it creeps back up to 73* F, drops back down as soon as the car exceeds 25 MPH .

I know R134a used lower pressures than does R12 but I don't know what's too much .

What you're running would be helpful .

TIA,

Hi Nate,

On my blue 300d I noticed my vent temps were creeping up. It just didn’t seem as cold as before. I was getting 35 F drop below ambient (45 at vent on 80 day) but now I was seeing 53F at the vent on an 80 F day…in other words a 27 F drop.

I’ve been tinkering around with it and I have come to the conclusion that I may have a combination of too much refrigerant and too much oil in the system. I put in two cans of refrigerant and 8 oz of oil.

I rebuilt the system with new hoses, pdf condenser, 134a and a R4 rebuilt two years ago. The cooling was sufficiently good but never ice cold. And it seemed to get worse this summer. I recall it being better.

My wild guess is that I put in too much oil and I’m choking up the bottom circuits of my of my of condenser. I intend to drain the entire system and start over again at some point. The car has sat a lot during the pandemic…does the oil accumulate down there if you let it sit? Anyhow, I’m finally admitting I don’t know Jack about AC and I will probably have it professionally evacuated, flushed, oiled and charged.