i kn its been asked...

dgatchc

here is the problem. the ac on my 1.6l 89 rt4wd isnt workin. its a sanden compressor btw. so i proceed to evac the system. then pull a vac on system for 30 min to 45 somewhere in this area. go buy a retro fit, put the first can in compressor starts, but not cold.( 45 to 55psi) as recomended. doesnt cool at all.compressor seems to be running, yet no cool. when i idle up pressure bottoms out. still no cool. dont know where to find pressure switch, have no gauge to fit high side. has a smaller fitting than my manifold.
am i beating a dead horse. please help. its hot and the wifey is ill at lack of air.thus the nag nag nag...can i bypass the pressure switch to remedy this issue. oh in the sight glass i see no cloudy look. but system maintains constant pressure

dgatchc

constant pressure while at idle i should say.

bam-bam

A high side reading would help with diagnosis, but since we ain't got one....

You say the low side bottoms out? Like zero or less? That would mean a system restriction, possibly a bad expansion valve.

If your compressor is engaging, the pressure switch isn't the problem. It will disengage below 35psi or above 350ish.

The system will hold approximately 30 oz of 134a, so 2 1/2 cans. If you've only added 12 oz, I wouldn't expect it to cool yet. Put another in and see what happens.

dgatchc

thanks for the answer bam. is the expansion valve something that can be replaced. on occasion the air has worked in the past. ima a 4 60 guy. usually i have the windows down but when my wife and daughter are in the car they dont like it. id love to get this working.do you have a drawing or diagram of the system. oh and even though i kn ur not supposed to could i draw a vacuum on the system from the high side if i buy an adapter for my high side port?

fast freddy

Agreed. If the ac system is filled correctly and still not cooling it could be a expansion valve or possibly the compressor shaft is broken. Need both high and low pressure readings to help you more.