I was at the car wash. On a whim, I washed out the AC condenser with soap and good water pressure while I had the hood open. I was amazed that it blew noticeably colder afterward. I'm thinking that 40 years of bugs and even more likely, a film of diesel particulates created an insulator on the condenser fins.

Beware not to let the excessive water pressure bend the aluminum fins. It won't do any good if the system isn't working anyway. Next week, I'm going to replace the serpentine condenser with a parallel flow one anyway. But, this was an amazing improvement!!!

There are condenser cleaners specifically designed to remove those pesky films.

__________________
When cryptography is outlawed, bayl bhgynjf jvyy unir cevinpl.

The built up crud also reduces radiator efficiency. One is the restricted airflow with the condenser in front and the other is the crud on the radiator fins reducing heat transfer.

You are correct, the cleaning makes a difference.

Good luck!!!

__________________
"Rudeness is a weak man's imitation of strength" - Eric Hoffer

I power washed mine a few years back. Thought I had trashed my 12 volt aux cooling fans because they quit working immediately after. Luckily after a while they dried out & started working again.

Are they markedly more effective than say, Simple Green?

__________________
1981 240D 4sp manual. Ivory White.

I would not use ordinary Simple Green on aluminum. Years back, the U.S. Army did some serious damage to a bunch of helicopters using Simple Green. Since then, Simple Green introduced an aircraft version of their product which isn't so hard on aluminum.

__________________
When cryptography is outlawed, bayl bhgynjf jvyy unir cevinpl.

Forgotten because it is out of sight, the evaporator cores also suffer from the same malady, restricted airflow/cooling reducing output. They must be clean for max cooling.

__________________
"Rudeness is a weak man's imitation of strength" - Eric Hoffer

Oof, that's good to know.

I've used it on both my condenser and old radiator a few times.

__________________
1981 240D 4sp manual. Ivory White.

Ive cleaned some really nasty car evaporators with viper foaming coil cleaner in aerosol form, it gets in there and pushes out the junk - you will then need to flow some water to get everything out and through the drain tubes.

for condensers - you can use it again or just use any degreaser gently.

__________________
2012 BMW X5 (Beef + Granite suspension model)

1995 E300D - The original humming machine (consumed by Flood 2017)
2000 E320 - The evolution (consumed by flood 2017)

Same thing applies to home A/C units....I fully clean mine out every other season and it makes a big difference. You'd be amazed how much junk collects on them in that amount of time.

__________________
-diesel is not just a fuel, its a way of life-
'15 GLK250 Bluetec 118k - mine - (OC-123,800)
'17 Metris(VITO!) - 37k - wifes (OC-41k)
'09 Sprinter 3500 Winnebago View - 62k (OC - 67k)
'13 ML350 Bluetec - 95k - dad's (OC-98k)
'01 SL500 - 103k(km) - dad's (OC-110,000km)
'16 E400 4matic Sedan - 148k - Brothers (OC-155k)

I washed out my evaporator with a garden hose. I just went in from the blower side. I shot some photos inside before and after with a usb borescope. It had a lot of dust in the fins that washed out of the drains.

Spraying the condenser reminds me of a pal who rigged up a wiper pump to spray his radiator and condenser when he flipped a switch. He did this when he drove his heavy camper over Tejon pass in summertime. I recall there are some signs that say turn off your AC as a public service announcement on the incline.

__________________
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

[QUOTE=ykobayashi;4174545]I washed out my evaporator with a garden hose. I just went in from the blower side. I shot some photos inside before and after with a usb borescope. It had a lot of dust in the fins that washed out of the drains.


What is the best way to access the evaporator to clean it? Pics?

I "stumbled" upon this guy a couple weeks ago. Maybe he's already well known (or, infamous lol) in "these parts"? Some "purists" will say he's a little unorthodox and heavy handed, maybe? Dunno. He seems to get good results and his vids are done pretty well. Give him a look. He has a bunch of W123 related common problem solvers. Seems like a nice enough dude.....not at all pretentious or on a high horse. I like how he just "goes after it".....lol
His "aux cooling fan rebuild" is really good. Check out his "channel".
https://www.youtube.com/watch?v=-ydCsCSxiiA&t=454s

You can't do that on a w124; you'd have to take half the car apart to get to that part.

And you will know this pass by the trail of the dead.

The last time I crossed the Tejon pass was over Memorial Day weekend.
The number of modern cars steaming by the roadside and their hapless drivers poking around the engine bay with bottles of aquasana was unreal.

__________________
1981 240D 4sp manual. Ivory White.