A/C recommendations for the MB vehicles - Page 11 - PeachParts Mercedes-Benz Forum

vstech · #1 04-15-2011, 10:08 AM

OK.
the A/C systems in our cars have plenty of obstacles to removing heat from our cabins.
Clean bend free fins and tubes should be the first thing any of us do to our car's a/c condenser, AND evaporator.
next it the fan clutch, and aux fan operation.

pressures in these charts are what we want to see with a proper operating system

This thread is going to be full of answers for our various automobile systems!

adding fans may help a little, but the problem with the older 123's lies in the huge series coil up front. it does not flow like 134 needs, thus lower volume of charge is required to keep the system operating... that low volume cannot handle the heat of the cabin without serious pressure spikes, and pressure is heat, it's a mad cycle.
IF you can find a condenser from an 85 123 it'll help a lot. but you'll still be pumping with an R4 compressor... are your windows tinted? light color paint on the car?

Quote:

Originally Posted by Manual Life

There are no leaks. The system held a vacuum for 4 months and has been good for a couple weeks. The recharge wasn't yesterday.

Oil added, none was in it. The vacuum could not reach 0 without the oil. I assumed I had a leak but that wasn't the issue. After adding the oil the vacuum reached 0. I don't know how or why. It was recommended by an old mechanic.

I can exchange the 134 but wasn't sure I could locate some 12. I assumed it was difficult to come by. I can unload the 134 at a friends shop at no cost, as is didn't cost me to charge it, but where would I locate some r-12?

a system with some pretty big holes can hold vacuum for months and leak out pressure in a few minutes.
to test a refrigeration system with an operating pressure of excess of 200 psi with less than 15 psi of atmospheric pressure is crazy and a really bad idea.
if it held, it proved nothing, if it leaked it destroyed the dryer and added moisture to the system... neither solution is helpful in testing a refrigeration system...

This thread is going to be strictly edited, and will include only approved A/C practices.
quality hints and tips as well as rules to follow!

Links to DIY and other Climate control articles

Quote:

84 300D

After a year and a half I finally got around to charging my A/C. It's so nice to have it and enjoy the quiet of windows up.

And, I assume if I doubled up on the fans for the condenser I would have cool air full time. As it is it warms up a little at idle and I am thinking this is the result of switching from R-12 to 134.

If that's not the problem let me know and what I can do. If it is the problem has anyone doubled up on fans? If so which fans?

Otherwise it works very well. I am happy to see how cold it is. I heard rumors that even a good a/c system didn't get very cold on these old cars.