[McLovin]

This is on an 85 BMW, but would also apply to 80s 911s.

The car was converted fro R12 to 4134 some time in the past.

I took the AC system completely apart, flushed out the evaporator, installed the biggest parallel flow condenser that would fit, high flow Spal fan, new Sanden 508 compressor, new expansion valve, hoses, etc. (In other words, everything is all new except the evaporator, and a couple of short hard lines, which I flushed).

I’ve vacuumed it down and it held at 29.x overnight so I’m ready to charge.

But then I thought this morning, why R134a?

The car was designed for R12, it doesn’t have the biggest system (evaporator, blower fan, air vents etc), and R134a isn’t as efficient.

I’m at a point where I could return and exchange the compressor for an R12 unit and replace one hose, and go to R12 instead of 134. So it’s easily doable, but it’s now or never.

Pros of R12:

(1) All things being equal, it’s going to give me colder air, I *think* that’s a certainty.

Cons:

(1) R12 is more expensive and you can’t just get it at the parts store (counter - I can still get it on eBay and it’s not that expensive any more because there isn’t huge demand any more, most have converted to 134. I don’t love the inconvenience but it’s not something I’d have to buy regularly).

(2) Shops don’t work on it? (I don’t know if that’s true, but I do it myself anyways).

(3) Future buyers might prefer 134? (I’m not worried about future buyers).

Anyone else stuck with R12? Good idea or bad idea?