AC - What's really needed for converting R12

[Jay Laifman]

In my Sebring, I have an R12 AC. It used to work well. It was just one of the various AC kits available in the late 70s. I have looked online at the possible R134a full kits. But none of them seem to have a blower/evaporator that fits as nicely as the one I have. So my question is if I get all the other stuff for R134a, is there a reason I can't or shouldn't use this blower/evaporator?

I spoke to one of the AC companies about the system in general. He said that the condensers I have won't work well with an R134a system. Anyone know if that's true? And if so, does the same go for the evaporator?

What is so special about the 134 condensers and evaporators? Do I really have to dump the system? Or can I succeed with using some of my old stuff?

 

[Brett Proctor]

R134a is not as efficient as R12 and requires a larger condenser.
If you do use the same size condenser the system wont cool the same as it did with R12a. How much less I don't know.

Also R134a operates at a higher pressure level.

As far as the blower and evaporator go, those you may be able to use, but I would check with someone that knows AC.

Also the lubrication is different between the 2 systems. I think R12a uses a mineral oil for lubrication and that does not mix with R134a Freon.

I don't know if its possible to flush the R12a completely out of the system so it wont contaminate the R134a.

You might do some searching on the web to see what others are doing who still have R12a systems and need it serviced.

 

[B57-1974]

I actually have experience with this. Just for the heck of it, I sucked the R12 from one of my cars using a high quality vacuum pump. I then put in R134a. While it does put out "cool" air, it in no way feels "cold". Also, I have read that the R134a molecule is smaller and it will leak out faster than R12. I don't have that particular car anymore, so I can't comment on that.

 

[Jay Laifman]

Thanks guys. I found another link that seems to echo what you are saying.

Some systems convert fine, others have issues. So since mine is custom to begin with, there is no way to know if it is one that will work - unless I get an AC tech who has done enough conversions to know the variables that matter.

Other issues:
Needs higher pressure, new compressor
Easier leaks, so need new "barrier style" hoses and seals
Problems when any R12 remains in any of system, turns R134a into jelly.
Condenser capacity and air flow specs are different

So it looks like I pretty much have to buy a new $1,000 kit if I want to get it working again. Or see if I can catch up to what Brett is doing and find all the right parts at a junk yard. (Or whatever they call them these days).

 

[Jay Laifman]

So Brett . . .

with your experience going through cars, do you have any suggestions? You have so many posts. I kind of get lost with a complete description in one place.

Like for example, if I go to a junk yard/pick apart, and look for a car to yank out its compressor, condenser, evaporator, fans, drier, expansion valve, do you have any suggestions on types of cars? Honda? Toyota? Or is there no way to answer that without seeing each one and figuring what will fit?

Also, I think that this evaporator looks very similar to the one I have in my dash - so much so that I think it will bolt into the same brackets. So if I do this, I might just start with this part, and try to get the rest out of a junked car.

Performa Series In Dash Evaporator