Problem with High Side/Low side Air Conditioning

[slag]

My AC is anemic. it blows somewhat cool, but not cold. its converted to R134a. Problem is, I evacuated the AC system last night and put a vacuum on it. I then filled it up up with a can of fluid and had to stop because my high side was at 350 psi and my low side at 40 psi. The air was still somewhat cool, but not cold.

I think I have an obstruction or blockage in the system. Where is the filter in the AC circuit and where is the expansion valve. One or both are plugged and need to be removed.

[slag]

I could also use a scan of an 89 AC system from the factory repair manual. My haynes manual doesnt show anything that I need for the AC system.

[Kyron]

R134a will not cool as well as R12, thats why with newer cars that have R134a they have a larger evap.

As for the pressures, I only know residential A/C... R22 :) and I'm to lazy to go look at my charts

[Oatmeal]

The expansion valve is in the evaporater(is that how you spell it?) housing, there is no in-line filter and you should have put a new filter/dryer in when you did the retrofit. I would check to see that your heater temp valve is all the way closed. Mine wasn't and it made a BIG difference. R134a runs higher pressures than R12 and I think you're only supposed to put in 80% of the amount you would of R12. So, something like 80% of 1.8 lbs(weight not pressure) Sorry, didn't have a calculator handy:rolleyes:I just did mine but I had to change out my compressor (used system) because, it was leaking oil. But, hey, it was getting down to 40 degrees, it just took a while to get there:eek: Got R12 in it now NICE! Anyway, hope that helps. Good wheeling!........Hans

[slag]

Thanks!

I didnt do the retrofit, it was like that when I got the truck.

I'll swap out the valve and put a new receiver/dryer in and go at it again!

Thanks!

Joe

p.s. What are your high and low side pressure readings on a typical day (70-90 degrees outside)

[Oatmeal]

Can't remember but, it's slightly (just barely) under charged because, I didn't want to open up my last, very valuable, can of R12. What happened was: When my heater valve was stuck open it wasn't getting as cool as it should have (DUH!) and my pressures were a little above spec (overcharging can cause poor cooling performance) so, I bled a little off (I know I'm not supposed to do that, don't rat me out) before I found the heater valve hanging open. The high heat load caused by the heated air sent the pressures up.:rolleyes: So, check your heater valve before you go to all the trouble, like I did.:o ........Hans