PeachParts Mercedes-Benz Forum - View Single Post - All of the AC facts in one place.. Divine intervention needed???

jay3000 · #1 07-29-2003, 11:23 AM

I know some of you are tired of reading AC posts from me, and quite frankly, I am too..

My system was originaly charged with some kind of blend of r-12, and 134a.. Readings were 400/50 @ 1500 RPM..I evacuated, and completely flushed the system clean as a whistle..

I did not replace the expansion valve that has R-134a stamped on the side. I was told by two different sources that it would work fine with r-12..

I put everythind back together, with new o-rings, correct amount of oil, new drier, and charged to the 2.9 lbs specified for the w-126 chassis with r-12.

The condenser fan is blowing.

The heater hose is blocked off with a shutoff valve.

THe compressor runs quietly..

At idle readings

ambient temp 85
Low side 45
high side 180
vent temps about 70
Low side return hose is cool, but not cold...

at 2000 rpm or so

low side 33
high side 250-275
vent temps low 60s or so
low side return hose is cooler than before, but still not ice cold

For reasons that escape me.. The system is simplty NOT making the evaporator cold enough to bring the vent temps down..

Looks like I'm down to two or three things.. Either there is something wrong with the compressor, the expansion valve, or the 2.9 lbs listed is overcharging the system???

Is it time for me to just take it to the AC shop??? HELP.....

Sincerley,
Jay Davenport