[302 Z28]

Originally Posted by LATECH

You would be suprised how many people dont know about running the HVAC on Recirc. If only they would read the owners manual...

Exactly, when I was working as a mechaic that is how I solved quite a few A/C problems.

Vince

[mitmaks]

Originally Posted by LATECH

No problem. O rings wont know the difference.
I would however see if there is an exspansion valve available for the R134.
Check to see if a 94 valve will fit, then use it.It is better calibrated for 134a . It will cool a little better, and more importantly keep the head pressure (high pressure side in the compressor) down so the compressor doesnt work so hard, and lives longer.
If you have O rings to replace the areas that you are dissasembling , use them. If not, as long as they are pliable, and are not deformed to the shape they are when installed under pressure, use them.When an o ring takes a set to a shape other than round, either circumferentially, or radialy they are NOT OK. Naturaly any O ring that is cut or split is a no brainer. Hope this helps.

Do I have to remove all the old oil (mineral) from system/AC compressor or would PAG be fine in it?

[LATECH]

Ideally you would flush it out and get it clean. Synthetic PAG mixes with ALL oils , that takes all the worry out. get system clean as possible, and assemble. It will be good to go.

[mitmaks]

I have another car and high pressure side needle is vibrating. What could cause this?

[LATECH]

compressor problem.. Like a weak cylinder, or a faulty reed plate.