R134 AC conversion

[467]

How is this working for the people that have done this? Does it
reduce the cooling capacity a lot?Thanks,Ward

 

[ken inn]

i sell a whole lot of a/c stuff for bmw's and mercedes. this is texas, and it gets HOT here. the shops that do the conversions all say they just flush the system, throw a drier at it, and change the fittings, fill with pag oil, and charge it up. in some cases, it will actually be colder than with r12. they say that in some cases, if the compressor is weak, that it will not be as cold, and, the compressor may fail. but it is not like a given. also, whatever mineral oil is left in the system will tend to puddle and collect in the nooks and crannies inside the system, and become a non factor. some also say that it takes a few minutes longer to cool down, but once it is going, there is no difference.

 

[467]

Thanks Ken, the R12 costs are eating me up. I am doing the installation of the parts but keep getting bad parts from mitsubishi. The parts costs are negligable becuse I can send most of them back, but the labor and costs of the R12 are $250 a pop. If I go with the R134 I can do much of the charging myself and save a bundle. It will probably be done better anyway.

 

[Tondar]

I currently have my engine and transmission out of the car and would like to get my AC ready for when everything goes back together. What should I replace/inspect so I can run R134a??Thanks

 

[ken inn]

it should be flushed with a special solvent, this is usually done with a machine, and then you should get a new drier. pag oil is also needed, some say you should change out the o ring seals, but no one does that any more. beware of places trying to sell you a lot more than you need.

 

[turboflanagan]

O-rings are so cheap and easy to do if you are opening the system I wouldn't skip them. There is a new (I think Viton) o-ring material that is supposed to be "new and improved". The new ones are red in color and do quite well in sealing and living longer than the green ones and much longer than the black ones. Also, I think that Ester oil is supposed to be compatible with both the r12 and r134a oils and will carry both through the system so you don't get the pooling that Ken is talking about. Absolutely put a new drier on and it is better to under charge just a smidge with the r134a, like 2/10 of a lb.
The main problem with this conversion is that it is a less efficient refrigerant and may not do as good of a job with the same size condenser and evaporator. It sucks in my K5 Blazer!Peter

 

[467]

You should be able to do it. It is tight but not real complicated. You will need a new Receiver Drier.

 

[ken inn]

i just did this last year. really easy. got a kit from pep boys for about 45 bucks, as long as your system still has some freon in it, what you do is evacuate the old r12, put on the new fittings, and charge it up. the new r134 stuff has dye and sealer in it, and it took me about 15 minutes. watch your sight glass, when the bubbles go away, you are done. blows just as cold as before. went thru all last summer no problems.

 

quote:Originally posted by 1101:
You should be able to do it. It is tight but not real complicated. You will need a new Receiver Drier. You tell me the part number for this or maybe what Mitsu calls it? I looked at partznet and didn't find it.

Thanks for your help.

 

quote:Originally posted by ken inn:
as long as your system still has some freon in itWhy do you still need freon in it? Is that so you know that it's not leaking before bothering to convert?

 

[467]

Try MB813459 Receiver Assembly. But double check it to make sure.

Ward


quote:Originally posted by dsmsleeper:
quote:Originally posted by 1101:
You should be able to do it. It is tight but not real complicated. You will need a new Receiver Drier. You tell me the part number for this or maybe what Mitsu calls it? I looked at partznet and didn't find it.

Thanks for your help.

 

It looks like that (MB813459) was the one!

Thanks

 

[ken inn]

one of my accounts in toledo is one of the best a/c guys in the nation. he has done thousands of conversions. he says as long as the system has not been contaminated; i.e, it is still holding freon, you dont have to do anything, just take out the old r12 and charge it up. works great for me.

 

The problem is that all of the lines and compressor have been in a box in my garage for a couple of years.

 

I was searching and found this old thread. Do you guys think that it would be reasonable to put the AC back on my car? I still have all of the parts.

TIA