A/C Compressor Issues

[lodac]

Hello,

I drive a 1994 740iL, I use to drive a 91 31iS but it blew up. anyways, I need someone that knows a bit about the A/C systems on bmw.. Its more about the compressor.

I recently had a leak in the A/C, the top hose on the Compressor was missing a O-Ring, I called BMA up and ordered the part, replaced it, filled it with freeon. It was working GREAT, no leaks, Nice and cool.

till today.

I hooked up the the low-side to check the pressure and it was bouncing below 30psi, from 20 to 30 when the Compressor kicks on and off. The compressor kicked on and off fast about every 10 seconds.

my question is what is the deal? is the compressor going bad?

[DaN]

What's the high side pressure at?

[AdamF 88iS]

Sometimes that happens when theres too much freon in there, did you overcharge it?

[lodac]

I have not checked the High side, I do not have the correct tools for that. I don't think I over charged it.. I only put in about 30 PSI, the low side show only 20psi in. The highside has cold piping. Any recommendations ?

what do I need to check the High side?

[lodac]

Okay, I did some more percise checking today.


while car was off the low side psi was into the 100's. Once started it would jump down to 10 psi then increase to 22psi and the compressor would kick in for about 1second then it would go back to 10 psi. and it would repeat this over and over till I shut it off.


I took some freeone out till the lowside psi was 45psi engine cool. I started it up and it continued to do the same.

[DaN]

If the lowside is at 45 psi with the engine off, it is way undercharged.

The correct way to charge it is by weight. There is a sticker somewhere under the hood that shows the charge weight.

You really need a gauge set, or an a/c machine to diagnose this correctly.

The high side should be hot, not cold.
Low side should be cold.