ac r134a not cold

1991 325i 4 door
the system was evacuated and new compressor installed and converted to r134a
system worked for a while but now blows warm
ac gauges show low side is 48 and high side is 50lbs
auxillary fan spinning like it should be
inside car temp 90 degrees
added 2 cans of r134 and temperature dropped to 60 degrees
pressure still 48 low and 50 high
compressor is engaged but not cycling, just constantly on.
tried a third can but it would not take any more and inside temp stays at 60 degrees.
can not read the sight glass because it is all scratched

any suggestions
i am thinking possibly the drier and a new presure switch. i have read that it is good practice to replace the drier when converting from r12 to r134a which of course i did not do.

thanks

yes you should change the dryer, you also need to change the expansion valve. did you flush the system? What type of oil is in the compressor? If high side reading is 50, that is way to low,and the low side at 48 is a bit to high ( that is why it will not cycling )

Originally Posted by a228380

1991 325i 4 door
the system was evacuated and new compressor installed and converted to r134a
system worked for a while but now blows warm
ac gauges show low side is 48 and high side is 50lbs
auxillary fan spinning like it should be
inside car temp 90 degrees
added 2 cans of r134 and temperature dropped to 60 degrees
pressure still 48 low and 50 high
compressor is engaged but not cycling, just constantly on.
tried a third can but it would not take any more and inside temp stays at 60 degrees.
can not read the sight glass because it is all scratched

any suggestions
i am thinking possibly the drier and a new presure switch. i have read that it is good practice to replace the drier when converting from r12 to r134a which of course i did not do.

thanks

Think you really should change the dryer and sounds like the expansion valve has definitely seen better days. Good luck.


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from a hvac tech side, sounds like the compressor isnt working. clutch might be working, but its not spinning the rotors inside

you my friend have valves that are bypassing...compressor no bueno