Hi, I have what I hope will be a fairly quick question.

I have a 2006 2.3l mazda3. The ac compressor seized about 6 months ago, no leaks.

I'm trying to fix it myself and have done the following:

(1) replaced the compressor with a salvage one and
(2) put a new drier in. I then
(3) pulled a vacuum on the system for about 30min at 28Hg, and
(4) made sure there was no leaks with vacuum off for 5min.
(2) While still under vacuum I put R134 in high side until pressure at low side read 14psi (per manual instructions), this only took an ounce or two
(5) then shut high side and added rest of can to low side (so about 12 oz of r134).
(6) static pressure (ac clutch not engaged) is about 100psi, 75F temp outside)
(7) turned car on and hit ac button, clutch engaged immediately and pressure on low side dropped to about 10 psi and then started to climb, roughly 10 seconds after clutch engaging the low side had risen to about 60 psi and was still climbing, at that point I heard some squealing and shut ac off. I looked over at high side and noticed it was lower than low side reading (but this was when the clutch was now off, didn't see value when clutch was engaged). If I let the system sit a few minutes the pressure equalizes across the two as you would expect.
(8) I took it to a local shop and they said the system looked clean and that it was my compressor.

I ended up buying another compressor, expansion valve, and receiver dryer to try it again. Unfortunately the same exact thing happened again and I'm at a loss as to what to check now. Any suggestions?

 

Just a bit more about it. This time I measured by weight. The manual says 17 oz for the weight. I put about 7 oz in by weight and turned the car on with the a/c. At first, the low side pressure dropped to less than 5 psi and climbed to about 60 psi with high side pressure at about 130 psi. At about this low side pressure, the belt starts to squeal or some noise near the compressor. With the compressor off, high and low side pressure is a little over 80 psi. The outside temp is about 95F.

One other thing. The manual says the system take 5.25 oz of oil. When I took off the original compressor, 2 oz of oil were in it. When I put the new compressor in, I added 4 oz to the compressor, 2 oz for the compressor and 2 oz for the refrigerant. This was all poured into the low side port and compressor was turned a few times by hand. So, the manual says about 1.50 oz should be in the condenser and evaporator total, so my 4 oz plus the 1.5 oz is roughly 5.25 oz.

Everything has been replaced now with new parts except the evaporator and condenser. While I haven't drained the oil out of either, the oil that has dripped out in between the connections appears to be clean and clear. The original seized compressor also had clean oil.