Just how cold were W123 300D's when the AC was new? - PeachParts Mercedes-Benz Forum

Carrameow · #1 03-27-2008, 06:32 AM

I am getting a liitle annoyed after i get into my 300D after every out of town trip. Every rental car I have been seems to have on demand instant freeze AC that cools you down in 10 seconds on a 105 degree day..

So this summer I am going to redo my 300D AC which is kinda "luke-cold" Trouble is is I think North American cars got AC as a retrofit because in Europe, humidity is not a big thing. Just how cold were 300D's off of the assembly line?

rs899 · #2 03-27-2008, 06:36 AM

I think they were cold enough then...but that was before global warming.

No actually I think they were always weak. The blowers don't seem very powerful.

JimFreeh · #3 03-27-2008, 07:16 AM

I've found them acceptable with R-12 here in high temp, high humidity Virginia summers.

R-134a makes them marginal, even at best.

Some have installed larger condensors and had success.

Strangely, the A/C units in my W114/W115 cars were ice cold....

Jim

t walgamuth · #4 03-27-2008, 08:09 AM

the 114 had the massive powerful and HEAVY york compressor, which I am told is not compatible with the new freon or not worth converting.

My 76 300d would frost the windshield or at least make condensation on it.

Tom W

#5 03-27-2008, 08:30 AM

I assume that they were just about like mine is now, since my system has been essentially replaced (except for the evaporator, which may be dirty). With R-12 it's as good as any 80s vintage car, but doesn't give you instant freezing air like a new car. More than adequate for 100F weather, but it takes about 1-2 minutes to get fully cold.

Shawn D. · #6 03-27-2008, 08:49 AM

The A/C in my '84 300td works extremely well in the Atlanta summers, even with the large cabin volume. The car is white, though.

leathermang · #7 03-27-2008, 10:11 AM

The old York compressors are fine as far as R134a is concerned per se (higher working pressure for instance) .... but are not acceptable these days due to size, weight, and lack of smoothness... they were much like Harley 45degree engines... huge masses moving back and forth... you can tell by the massive steel support structure used to hold them.... my parts 79 wagon had one... They also had the advantage of having an oil sump... so they were not in the classification of the Delco Scotchyoke of being so prone to failure if your refrigerant was a little shy of perfect in moving the oil necessary for lubrication around the system.
The York had two cylinders.... the Delco has four ( and is also kin to the Harley example).... and most compressors today have six cylinders ( with the direction of travel and work changed to the longitudinal axis )... you can see the progression to smaller work per unit of crankturn and better hiding of the motion to minimize vibration.
If you bring your MB back to stock out of the factory I am sure you will be pleased with it.. remember first that air across the condensor is the primary limiting physics rule ...and that you will HAVE to clean out the evaporator... see DMorrison's thread about how dirty those can get over the years....

whunter · #8 03-27-2008, 01:16 PM

Quote:

Originally Posted by Carrameow

I am getting a liitle annoyed after i get into my 300D after every out of town trip. Every rental car I have been seems to have on demand instant freeze AC that cools you down in 10 seconds on a 105 degree day..

So this summer I am going to redo my 300D AC which is kinda "luke-cold" Trouble is is I think North American cars got AC as a retrofit because in Europe, humidity is not a big thing. Just how cold were 300D's off of the assembly line?

Averaged across twenty new W123 chassis:
38F - 42F

A very good technician can get a perfect W123 R12 system down to 34F without slugging the compressor.

Last year my 300SD was reading output air at 33F.

The compressor clutch failed last week, after only 272000 miles.

Have a great day.

rrgrassi · #9 03-27-2008, 01:48 PM

I wish there was a way to make the GM A-6 compressor fit. Those are good ones, and also have an oil sump.

ascalise · #10 03-27-2008, 02:02 PM

Bought my 240 with a complete ac that didnt have any freon in it. I went through it to make sure the compressor worked and everything was tight a few weeks ago and just recently evacuated it and charged it back up and it blows 33 degrees on low out of the vents even on a 90 degree day. Now if i could only keep the engine below 100 degrees i would be set. Btw, my blower works great, it moves quite a bit of air.

leathermang · #11 03-27-2008, 02:04 PM

Quote:

Originally Posted by rrgrassi

I wish there was a way to make the GM A-6 compressor fit. Those are good ones, and also have an oil sump.

Amen.... have you investigated the situation ? Are they just too big in the wrong direction....or are you ( correctly ) assuming that the plumbing would be a nightmare process ?
I am considering this myself... so any 'peanut gallery' comments no matter how wild will be considered helpful....

pawoSD · #12 03-27-2008, 03:05 PM

Can I expect that my compressor will still work if the system was R12 and was then recharged with R134a (by idiots) and then started stalling the engine at idle, I then cut the belt, and disabled the system. (4.5 years ago) However, I can grab the central shaft of the compressor and rotate it by hand easily and can feel it "pumping/compressing" on each rotation. Think its ok? Or will I clean out the system/recharge it and have it die 100 miles later?

I'd love to have A/C, it just seems like a huge amount of hastle/expense for a potential-constant failure.

#13 03-27-2008, 03:10 PM

I would probably just replace the compressor instead of having to (potentially) go through the whole ordeal twice.

pawoSD · #14 03-27-2008, 03:13 PM

Quote:

Originally Posted by Craig

I would probably just replace the compressor instead of having to (potentially) go through the whole ordeal twice.

Thats what I figured. I'd probably have to buy a new one and not re-manufactured right? I've heard bad things about re-man ones. I might do this as I really don't want to have to sit in my car in this summer's humidity and heat again...it was bad last summer. Especially if I get a nicer job after I am out of school, I can't be showing up sweating to death.

Though, if I get a good job then I could afford to have the A/C redone....