Thanks for the suggestions. An update for posterity: The valve had initially tested OK when I first pulled the evaporator out. It started honking after I cleaned the mineral oil out with A/C Flush solvent. I added a couple of drops of PAG 150 oil to the inlet of the valve and re-tested. The valve st...

Hi John

Thanks for your reply.

I was trying to follow the guides I’ve read here and tune it down for 26psi.

I’m just not sure if the fluctuating gauge reading while blowing air through the valve is indicative of a faulty POA

Cheers

Hi everyone, My name is Matt, I live in New Zealand and have a 67 Buick Rivera that I've owned for about 13years. I'm going through the A/C system in my Riv (has never worked in the 13 years I've owned it). I was bench testing and trying to set the POA Valve for R134a by blowing ~100psi shop air thr...