Greetings all. My 300SD blows cool (at best). System converted to new freon by previous owner. Local MB tech tells me that this is typical for older MB conversions to new freon. BUT. Wife's 1980 280SE with new freon conversion will freeze you out of the car.

Serviced AC last spring. System worked last summer, but blows cool-only. I tolerated the tepid performance last year-and always tried to park the SD in the shade.

AC serviced Friday. System purged and new freon added to specs. Again, AC cool at best with all controls set to maximum cold, and blower at max air.

What gives with this thing? Any suggested fixes? Would a diesel station wagon compressor put out colder air if I changed out?

Plezhepme.
Jones

Well, you are new here so I will point out a couple of very important things you can do and think about first...
But long range you need to do a search and read the vast quantities of great information already in the archives...

Your car was built in Germany and used R12... a chemical not naturally found in nature.... a chemical specifically designed by engineers to provide the most efficient and safe method for cooling your car.... Most other referigerants are either less efficient or hazardous in one way or another...

Short term on your car... be very sure your condensor and radiator are clean and the fins not bent... this makes more difference than most people realize...

Next, find a way to get to your Evaporator box and clean the fins there... DMorrision's post about this...and the pictures of the junk which had accumulated over 20 years of this not being serviced convinced me of how important .... at least once every 20 years... cleaning of this is...if air can not go across the condensor and evaporator you can't expect a system to cool anything... seems obvious.... but cleaning the evaporator is not listed in any regular maintenance list I have ever seen... it is something needed on cars which are still working when the others have been recycled into ovens.

And with that other refrigerant in your system.... be SURE not to overfill it... or you will lose even more than the ability which you have already lost by not using R12....

Will drag out shop manual and check location of
evaporator. Any chance of getting a link to the
post you referenced?
Jones

That subject should be somewhere amongst these... several of which are also great threads...

http://www.peachparts.com/shopforum/search.php?searchid=309326

Not a job for the faint of heart, unless you know the evaporator lay out IMHO, but I've done it. See post #12 on this thread: http://www.peachparts.com/shopforum/showthread.php?t=97592&highlight=test+tube+evaporator

__________________
The Golden Rule

1984 300SD (bought new, sold it in 1988, bought it back 13 yrs. later)

Bruce, The combination of DMorrison's instructions (included in my search list above ) and your post ought to allow someone to do a much easier ( but not easy ) job on that deal...