ac pressure specs e30

does anyone have the low and high pressure specs for a 1991 325i e30 4 door factory ac system.

I had the system evacuated put in a new compressor and switched to r134a. On a very hot day the ac is luke warm. in the mornings before it gets hot the ac will be cool.

I have manifold gauges and i want to do some diagnosis but need to know what the low and high pressure should be.

thanks

not sure of the pressure at the moment, but the evap temp (on your suction gauge) needs to be around 40' (somewhere around 40-45 psig i believe). you should have sweat on your suction line up to the compressor, but NOT on the compressor itself. if i get a chance, i will get my gauges and get you an acurate #...

the best way, since these are the r12 originally, then 134a numbers will be off. the best way to do a good check, wait till its low 90s out and add some 134a until it blows cold. what youll want is a thermometer to put in the vents and youll want somewhere around 40* comin out.

with 134a gauges, 40' evap temp is 40'. there is no "off" to it. pressure/temp charts are a constant. 40' on r12 is 40', the pressure is different, thats the only difference.

Originally Posted by eieio4tn

with 134a gauges, 40' evap temp is 40'. there is no "off" to it. pressure/temp charts are a constant. 40' on r12 is 40', the pressure is different, thats the only difference.

i was mainly talkin the air comin out of the vents.

anyway...we both agree on the temp. to achieve a 45' supply air, the suction pressure would have to be @ 30 psig, which is 34'. head pressure should be in the 150-180 range.