PeachParts Mercedes-Benz Forum - View Single Post

James L · #43 06-20-2005, 10:27 AM

I put gauges on my 1993, W124, OE 134A car yesterday for evaluation. It has been cooling good but wanted to check to aide your 1994 and see if it is under charged, overcharged or any air in the lines? Here are my parameters:

Ambient (outside air) 82-85F, Humidity 40-45%, Shade, 11:00 am:

engine off (cold): low side 90 psi - high side 90 psi
engine on, a/c on: low side 30 psi - high side 195 psi

aux fan comes on: low side 20 psi - high side 245 psi
(takes it back to 30/190)

bridge for aux fan on all time: low side 30 psi - high side 190-200 psi

center dash vent 41F

engine off (hot): low side 55 psi - high side 125 psi

no bubbles or foam in sight glass at any time or test, system has yellow dye in it and no visible leaks anywhere or in evap drain!

My system is cooling good and I am getting low dash vent temps (have had thermometer in dash all week) but I feel it may be slightly undercharged?
Also 2 years ago a tech put 1/2 a 12oz 134a can in with low side suicide hose and up/down roation of can. (before I knew better). I wonder if it would be good to discarge, evacuate and recharge? How do I know if any air or moisture is in the system? I will probably leave the sytem alone since it is cooling good but the 95F + days have not arrived yet!

Advise and opinions sought and wellcomed