R12 to R134 Conversion Question

wcc · 06-12-2007, 04:44 PM

To convert R12 to R134 is it as easy as changing the fittings on the compressor?

rcecale · rcecale's Garage

It's probably best if you have a shop do it for you. You have to evacuate all of the R12 out of the system before you can install the R134. They can't co-exist in the same system.

Randy

wcc · 06-12-2007, 05:04 PM

I've had the system evacuated already and I replaced the expansion valve and the belt. So now it's ready to be charged. I'm just wondering if I can just change the fittings and use the R134 instead of the R12. If it leaks out really quick then I'll look into those barrier hoses.

the · 06-12-2007, 05:13 PM

I was at a local car parts place the other day, and saw a $49 R134 kit.

Basically, the instructions said (1) evacuate system, (2) change the fittings, (3) put in the 134.

That seemed a lot easier than I had thought.

shbop · 06-12-2007, 05:17 PM

Don't forget the oil>

wcc · 06-12-2007, 05:19 PM

Quote:

Originally posted by the
I was at a local car parts place the other day, and saw a $49 R134 kit.

Basically, the instructions said (1) evacuate system, (2) change the fittings, (3) put in the 134.

That seemed a lot easier than I had thought.

That's why I'm asking cause it seems too easy. But that would be a nice to have an easy project for a change....

rcecale · rcecale's Garage

Quote:

Originally posted by shbop
Don't forget the oil>

You can't just add more oil to the system. R12 oil is different that oil for R134 and they cannot be mixed.

Basically, getting rid of the "hazmat" is the tricky part of the job. Once you've got that done, you're home free. Just make sure yu put the new valves in the proper locations.

Randy

MBAtarga · 06-12-2007, 06:08 PM

You also want/need to change out the drier.

johnman001 · johnman001's Garage

I think what I read is that the rubber lines really should be changed as well as they will leak R134a. Barrier hose is recommended.

The compressor (unless thoroughly cleaned) will probably fail shortly after introducing the R134a. The oils and seals used just are not 100% compatible. Get a rebuilt or new compressor.

Like Mark said, you will need to change the drier as well.

I investigated this and actually have the parts to do mine, but have not yet gotten around to doing the change-over.

Don Plumley · Don Plumley's Garage

I've done a little research on this for my kid's car.

There's a perfect way, a reasonable way, and a bad way.

The kit in the autoparts store is the bad way. They use an oil that's missable in both R12 and R134. But it would only work to salvage a system that's too costly to repair - and cooling would be lukewarm at best on a mediocre system.

The perfect way is to replace the compressor, receiver/dryer, flush the condenser, replace the oil, deep vacuum, then charge with R134.

The reasonable way is to replace the R/D, blow out the oil in the condenser, replace with PAG oil, deep vacuum, then charge with R134.

The problem is that R12 does not need as much compression as R134, so it wears the compressor faster and does not provide as efficient cooling. In the big picture, you are probably better off staying with R12.

javadog · 06-13-2007, 03:19 AM

I once had a shop that did a long distance PPI for me, convert a car I was buying from R12 to R134, without my knowledge. Naturally, he did it without changing all the important parts and the system was essentially useless afterwards. These systems are marginal on R12. On R134, they are utter crap, unless you re-engineer them.

Stay with R12.

JR

wcc · 06-13-2007, 03:31 AM

There are a couple of places in town that still do the R12. I'm going to take it in on Friday and have it charged up. It's about $50/lb and about $30 for labor if anyone is wondering what R12 is going for.

Tim Hancock · 06-13-2007, 04:24 AM

Bill, I charged mine with 134 a couple years ago and am quite pleased with it still. DIY 134 conversion in SC complete!

Let me know if you want to chat about it, I can PM you my cell number.

After two years, I just had to add one cheap can of 134. Pretty good considering it still has stock hoses and an old York compressor.

Oh Haha · 06-13-2007, 04:48 AM

Bill,
There is another option:

Rip all of the hardware out and lighten the car up!!

j/k I know Sandy likes the air.

We'll see how much MY wife will put up with this weekend on the drive with the new seats and no air. Oh, it's supposed to be 91 degrees that day. Woohoo!!!!

DB_NC_95C2 · 06-13-2007, 08:38 AM

Whole hog is the best bang-for-the-buck.
I needed to keep A/C in my SC for this climate. I had read enough about old hoses leaking R134A so chose barrier hoses, my compressor needed either a rebuild or replacement so new rotary seemed an obvious choice, and in addition chose a new evaporator and 'procooler' (receiver/dryer) from Rennaire. I'm extremely happy, it was just another one of the many 'upgrade when time to replace' choices I've made. On all but the most unbearable of days (around here that means mid-to-high 90s and soupy humidity) it's quite comfortable in the car. No, due to the limited vent space it isn't like a modern car, but very liveable. So I would recommend if you're doing A/C stuff, use the same mantra as that applied to someone shopping a 911, i.e. "choose the most that you can afford"

jeff1hughes · jeff1hughes's Garage

I believe that it is ester oil that is compatible with both systems. Most of the do it yourself kits come with a "charge"(presurized) can of this type of oil that you can put in. Before doing this I really recomend flushing your system out. You can get something like Dura 54 (NAPA) to poor into the disconnected lines, then use shop air to shoot it out the other end (disconnected too!). I've also heard that you can just use brake cleaner too. Do this with all lines, through the condensors and evaporator (not the pump or the drier). Oh, and when you do this, make sure you put on a new drier - it just has to be done, they're only like $35-$40. And by the way, R134 really doesn't just leak out the hoses in a year. Systems that leak that quick have a bigger leak somewhere else!

rnln · 06-13-2007, 08:11 PM

wcc,
becareful, someone told me they have/use R12 but when the car is in the shop, they used Freeze 12. If you argue, they said this is R12 compatible. It lasted me several weeks.

The second time I did (actually the shop did), with a lot of research and questions on this board. Evaculate all R12, test leak, replace dryer, conversion kit (adapters), then pump 134. It lasted me several weeks now and still cold. I am crossing my fingers.

wcc · 06-14-2007, 04:04 PM

Update: I changed the drier today and had the system evacuated. It held a vaccum and then they charged the system with R12. It took 3lbs. I gotta say WOW it sucks bad! Around town you might as well forget it and on the E-way with the RPMs around 3k it blows cool on high. Anything less then high it's cooler then outside air but not enough to make a difference. This project was a waste of time and money.

Thanks a lot for talking with me about it over the phone Tim. I really appreciate it.

rcecale · rcecale's Garage

That does suck!!! and it's also the same experience I've had for the past few years.

This year, I decided to try something new...my mechanic charged me $300 for the whole conversion and R134 charge. I now have a system that works WAY better than it has with R12.

On the drive to work in the morning, it's usually low - mid 70s outside. I can barely run the thing, it gets that cold in the car.

During the day lately, it's been high 80s, low - mid 90s... My car parks in the sun all day, so it takes a few minutes, but it really gets nice and comfortable inside.

It just might be worth the investment to convert.

Randy

billroth · billroth's Garage

Randy,

What exactly did your conversion entail? Evac, flush, dryer and charge? Or was there more to it?

Lawrence