What's the deal with parallel condensers? - PeachParts Mercedes-Benz Forum

Hit Man X · #1 11-20-2013, 09:26 PM

Quote:

Originally Posted by Randy

I considered changing the condenser on my '86 420SEL once; I learned there was a parallel-flow condenser for the Diesel 126-series right before the 126 was phased out: Mercedes-Benz genuine part, can't comment on if the fittings are in the same place, but they probably would be.
I admit I have not been able to get more than marginal performance from my car's refrigeration system in the 10 years I have owned it. It had been converted to R126 when I got it.
I think I will have to remove the dash and start from scratch. Perhaps the evaporator is dirty; the air flow seems fine, but it would only get cool, like air outlet temps of 65-68 degrees, at best. I did not buy the condenser because when I turned a water hose on the condenser, it made little to no difference, so I wondered if that was the problem with mine anyway.

ALL W126s received the same small tube and fin condenser starting late '84 build for the '85 MY...just like my 10/84 300SD. Compare the '84 MY and earlier versus the '85-91 and you can see how much smaller the tubes are in diameter. This increases surface area vastly to cool the condenser. Fittings are in different spots between the V8s, I6 gas, and Diesel.

NO W126 ever had a parallel flow condenser from the factory.

The performance in my cars is more than adequate when I am in Houston on R12, which is extremely humid and quite hot in the summer also. Even in Houston when my 560 was on 134A it cooled decent around town and far better down the road, but that is to be expected. If you cannot get out of the upper 60s for vent temps on 134A in a V8, you have other issues.

Why people try to save a few dollars by using 134A versus R12 is beyond me. Buying three cans of R134A for ~$40 at Wallymart versus ~$100 for four 12oz cans of R12 on Craigslist to save $60 but reduce cooling in a volatile climate seems like false economy.

eatont9999 · #2 11-21-2013, 11:57 AM

Quote:

Originally Posted by Hit Man X

ALL W126s received the same small tube and fin condenser starting late '84 build for the '85 MY...just like my 10/84 300SD. Compare the '84 MY and earlier versus the '85-91 and you can see how much smaller the tubes are in diameter. This increases surface area vastly to cool the condenser. Fittings are in different spots between the V8s, I6 gas, and Diesel.

NO W126 ever had a parallel flow condenser from the factory.

The performance in my cars is more than adequate when I am in Houston on R12, which is extremely humid and quite hot in the summer also. Even in Houston when my 560 was on 134A it cooled decent around town and far better down the road, but that is to be expected. If you cannot get out of the upper 60s for vent temps on 134A in a V8, you have other issues.

Why people try to save a few dollars by using 134A versus R12 is beyond me. Buying three cans of R134A for ~$40 at Wallymart versus ~$100 for four 12oz cans of R12 on Craigslist to save $60 but reduce cooling in a volatile climate seems like false economy.

84-85 gassers have the better condenser as well. Both of the condensers I have were salvaged from 420SELs. The main difference is the smaller tubes and more parallel runs. The older condenser has something like 12 runs while the upgraded condenser has something like 16 runs. I counted them once but forget the exact numbers. In effect, the surface area is increased in the later condenser. Upgrade the fan as well or your cooling at idle will be poor.