I recently had to convert my '89 740GLE over to R134 due to a leak in the high side line that runs along the engine compartment. After running a leak test using the special dye, was told by the mechanic that this was a commom problem because the lines would develop leaks due to the moisture that would collect in between the rubber grommet that holds the line to the frame. Besides the lines, the only other thing that was replaced was the receiver/dryer. I'm assuming the system was completely evaccuated and then and was charged with R134.

Now for the questions:
I've read a lot on Brickboard about the fact that the oils are incompatible. And then i've read that the POE (ester) oil IS compatible with the mineral oil. I know for a fact that the compressor was not removed and drained of the old (mineral) oil. Should I be concerned? Second question is that I'm having cooling problems at an idle. Currently getting a 70 degree temp on a 92 degree day. Once i begin moving, it drops to 54 degrees. I'm pretty convinced that this is due to the fact that the electric condensor cooling fan does not appear to be functioning. The fan should run the minute the A/C is switched on, correct? I plan on testing whether or not this is due to the thermoswitch in the radiator by disconnecting the 2 wires to the switch and jumping with a paperclip (as suggested in previous threads). If the fan works, I know it's the thermoswitch that's the problem. I'm also intrigued by the the Smart VOV's ability to drop the temp another 5 - 10 degrees. Final question is if I add the Smart VOV do I need to have the whole system evacuated and recharged with R134? Or would you recommend Freeze 12, the other EPA approved product instead.

Ron
'89 SilverBrick740
109K