Compressor siezed while not in use

[KPT]

So my truck wasn't driven for almost a year.

Compressor clutch would not engage when I tried to use the AC after sitting for a year.

I put some gauges on it, had 11 psi at maybe 70 degrees ambient. There was a puddle of oil under the compressor but it appeared to be ATF (there is Mobile 1 ATF in the PS pump). I put in a can of 2 ounces PAG 100 and 1 ounce 134a to be safe. Then put maybe 1/3 of a 12 oz can of 134a, both into the high side. Gauges had 50 PSI now at 80 deg ambient so I turned on the AC.

The engine bogged a little, compressor would turn 1/4 to 1/2 turn randomly and the compressor clutch started smoking, pulley was spinning normally the whole time.

Would moisture in the system cause this? Shouldn't have been any in there though, I've owned the truck since 2001 and have no reason to believe AC was ever serviced before.

I'm not 100% sure the mystery fluid was ATF, heres where it is:

It does not appear to be the right color for ATF, even if it had been burned by engine heat there:

Is that the right color for refrigerant oil? There was no noticeable leak from where the lines bolt to the back of the compressor.

Sorry for the long post, I'm obviously new to the AC field and trying to learn all I can.

 

[TheJackal]

Hmm... I think the oil in the system might be a little lighter in color than that, but if it picked up contaminant along the way it could have caused it to be a little darker... but then again I could be wrong.

Typically, though, a florescent leak detector dye is added to the oil which gives it a bright greenish-yellow appearance. IDK if it comes from the factory this way or not, we'll have to see what someone else says about it. If it does, and you're certain your system has never been serviced before, than you could rule out the possibility of an oil leak.

 

[IZwack]

Yes it is often a very bright green-yellow color.