Buick AC, freezing POA valve, warm air

[Cusser]

I received my gauge set yesterday. Gonna measure this weekend. Does a low pressure on the high side indicates a bad compressor? And how can I measure if the expansion valve needs replacing?

Measure both low and high side pressures at about 1800 - 2000 rpm when running AC a few minutes. Post those.

When the high side pressure is low, that can indicate low level of refrigerant.

[GearVirtuoso]

yo, nice one on getting that gauge set. it's gonna be a game-changer. Low pressure on the high side could mean a bunch of things, not just a bad compressor. It can also signal a stuck open expansion valve or even s low system charge. So before you go replacing stuff, you gotta diagnose it right. As for the expansion valve, if it's stuck open, you’ll see a low pressure on both the high and low sides. if it's stuck closed, high side pressure would skyrocket while the low side drops. Cool stuff on the Pontiac too. Refreshing those old hoses can do wonders, so go for it.

[Gustav4523]

@thebandit

Too cold here now to get good readings. I found a great video from Chrysler Mastertech that explains a lot: https://www.youtube.com/watch?v=qNwStH5573c