1993 MM ac converting to 134a or no?

[Bbrooks00]

Just bought my 2nd MM, repairing the ac, (hvac tech by trade)
Just finished replacing the head gasket, is worth converting the system to 134a?
I have some r12. I just want to do whatever is easier. It was low and I added gas just to
make sure the compressor ran, it does run but I was running 5/150 So I ordered a expansion valve
drier and gonna flush everything. Is it worth sticking with r12 or switch to 134a. Open to any advice!

[geezer101]

Hi and welcome to mightyram. I would consider you use an alternative like hychill minus 30 (you do this stuff for a living so you'll know about hychill, if not click here) I'm not super knowledgeable about A/C but I know the older refrigerants are being phased out due the harm they can cause. 134a doesn't seem to be as efficient as R12 and might stress an older A/C system, so the hychill seems like a good option.

[Bbrooks00]

Thanks I appreciate it, I have several pounds of r12 so that isn’t really an issues. Just didn’t know if the common practice was to go ahead and swap it

[claych]

1'st , Welcome !!!
2'nd , 5/150 is ???
Thx

[Bbrooks00]

5 suction and 150 head, I assumed the drier and or valve were plugged

[Bbrooks00]

Suction and high side pressures. I assumed the txv and or drier was plugged so I went ahead and ordered them

[Chargerx3]

Mine was weak on R12 so i topped it off with 134 and new fittings. I know its not recommended without changing o-rings and oil, but its runs fine and Very....very cold. Love it.

[dash]

many folks top up with R134 and say they change nothing & 'Works fine'.
You're only cooling a small pickup cab = 'half a car', so.....
An SUV with no window tint at mid day in miami may be a different story
My old 1986 corolla hatchback(R12) got 'freezing cold' under such conditions
Also, the majority has no access to R12
Quite a few old school mechanics/techs, say the AC gas was all a money making BS scam

[Bbrooks00]

Changed txv,drier and blew all the lines out, added 4 oz of pag100 and 24oz of r134a and that did the trick

[claych]

^^^
So the txv (bulb charged with r-12?) is a non issue?
pag100... the 100 is a viscosity rating?
Thx for the input, much appreciated !!

[Bbrooks00]

it was a 134a valve
yes pag 100.