What's the normal low-side pressure for a 134a conversion? I think I may have overcharged mine. It doesn't seem to cool real well.

 

My manual says 21 - 36 psi for the low side, and 199 - 228 psi high. THat's for a factory R134a system.

 

I think that's what mine is. The high side is closer to 250. I used the pressures listed in the 134a manuals, but I'm not sure they are correct for a conversion. The cooling is rather disappointing. I know 134a doesn't cool as well as R12 did, but I expected better.

The new recvr/dryer doesn't have a sight glass, otherwise I use it.

 

What year and engine size? The new reciever drier should have a sight glass its just painted over, try scraping the paint off of the top where the sight glass would be.

 

Yeah, once my A/C went out, I got the hose from a seller on here, put it in and had it evacuated and recharged, and it's not as cold as it was. But it still is cold and that's what matters...

 

It's a 88 22RE with a 134A compatible r/d. There's a hex plug where the sight glass would normally be. I guess they want you to fill the system using the gauges only. Rather annoying actually.

 

update: I looked again and there was a sight glass down in the hole covered with paint. so that is fixed. It does look like it's overcharged.

I'm curious though, is there a different expansion valve needed for 134A? The pressures look pretty normal for R12.