sbagdon

Got a '92 RN81 with r12 that was converted to r134 pre-purchase, and it's never worked (and not really inclined to put the time/effort into "fixing" it). Might have an oppurtunity to purchase a '94 parts Pickup, so have to ask... has anyone ripped out the entire r12 system, and installed an entire r134 system? Is it mechanically doable? Presuming that as long as the high and low pressure switches report back "ok", then the compressor will engage, and compression, expansion, and cooling will occur as normal.

Would prefer no "just get a '94+", "fix the r12 to work with r134", etc. Have no issues taking on these little retro-fit projects, just one of those people. More of a question of mounting (compressor, condensor, evaporator, pipes, etc), yet as it's an a/c change mid-gen, figured Toyota made the new a/c system fit to the old mounting points. Yet looking for input regarding any challenges, such as mounting, electrical, etc.

Thanks!

waskillywabbit

iTrader: (-1)

Be a lot less effort fixing what you got than ripping out and starting over.

:wabbit2:

sbagdon

Well, did say would prefer no "fix the r12 to work with r134" replies, yet hey... we don't always get our preferences...

Don't disagree it wouldn't be less effort, yet still looking for anyone who's done this, or has any input on mechanical or electrical challenges that might come up. Thanks!

sechott

Just had my 88 converted to 134a took it to a shop paid $100 for the new fittings installed and charged It blows cold air even colder than my wife's 2010 civic. I was told the shop I had a little leak in the compressor and will need to be replaced. Been 2 weeks and I can tell it is not as cold now. next spring I will get a new compressor and get it recharged I shouldn't have anymore problems, I hope.

sbagdon

Still looking for input on replacing, not converting...

The current r12 system is leaking like a sieve, and the future r134 system "isn't working". So either way, something is getting "fixed". Preference is to install the r134 system, and fix that.

Anyone?

Thanks!

gandude

R134a is on its way out. ...if you need R134a, stock up now.

I would go the cheapest route.

http://green.autoblog.com/2011/03/04...t-in-vehicles/

Rerunn

To properly do the 134 I'd replace the condendsor, drier and maybe even the evaporator. The compressor really depends on the vehicle. By replacing these components you should rid the system of the 12 and the oil.

sbagdon

Going by that story, figure we won't see r1234 delivered in new cars until my14, if not my15, and no complete retirement of r134 for 3-4 years after that. Believe r134 started around '94, and believe the last r12 was '97, so we'll probably see that same pattern. So we have probably 10 years left of r134, at least?

Going by experience with the '93/'94 MR2 split, everything changes, because the pipe's diameter changes. Not a single component was compatible with the other system, so if you were to replace (for example) the condensor, you'd have to replace the input/output pipes. And considering how badly r12 and r134 work with each other (or at least the lubricants built in to the system), would rather start with a system that never had r12 in it to begin with. Presumption is that the biggies are the compressor (how, and how much, it compresses) and the expansion valve (how it expands). Seem to remember you could technically buy a r134 expansion valve for an r12 system, yet the labor costs made it prohibitive (let's not go there). Yet when/if, everything would have to be replaced, as a unit.

This would be a total swap over, not a minimal-effort retrofit. This was more a question of if anyone had done this, or if anyone was aware of a mechanical (mounting point changes to the frame, etc) or electrical (pressure sensor or clutch plug, etc) issues from the swap. Seems logical that as long as the high/low pressure switches tell the a/c relay that all is ok, and the clutch engages, then refrigeration will occur. Yet always prefereable to know what drama is coming (if any).

Dirt Driver

Do you know for sure that the '94 parts truck has a 134a system?

sbagdon

Nope, haven't yet looked at the Pickup. Yet it's presence (or not) would contribute to the decision process.

Yet this project will go forward, either with this Pickup, or another.

gandude

I think you are right. But, R134 will go up in price as the years go by.

If you are going to do a complete system, might as well go with the latest (if compatible). The engineers agree that R134a was a poor refrigerant. The new stuff is presumably much better.

Rerunn

That's correct but some hybrids are running 1234 already. Worst part is....stuff is flammable.I

sbagdon

Won't disagree with that price-analysis. Not necessarily by regulation... by supply/demand.

Going to disagree with the engineers, in that r134 wasn't "better" or "worse", it was just "different". You can get the same temps out of r12 and r134, you just have to design the system to the temps required. Seem to remember that r134 requires more refrigerant, at higher prssures, with a more efficient condensor, and different expansions valve spray pattern. So if you're saying that a "bigger" system requirements makes a poor refrigerant, guess that can be agreed to. r12 was darned good at what it did. seem to remember it required not much compression, easy condensing, and easy evaporation, and you'd get great refrigeration. It's just that it killed the environment. Then again, if those are your requirements, then just go with ammonia refrigeration. Then agan, when that leaks, you don't kill the environment... you kill the operator.

Agree that if you're going with a complete system, then go with the latest compatible. And hence the effort to find a complete r134 system, taking r12 completely out of the picture.

Can't find any car in the US currently shipping with r1234, and can't find anyone selling a shop setup for r1234 (at least not Robinair). Not saying you're wrong, yet can you point out a specific US model. Wouldn't be surprising if they are shipping in the Europe market, just not seeing them in the US market.

Intersetingly, it's showing that r1234 will start out at 10x the price of r134. Yet at least most of the tools will be compatible, though it appears you'll need to have two sets (as you don't wnat them to cross-contaminate).

Dirt Driver

What engineers?

Rerunn

From what i heard at an AC class the 134 and 1234 are in no way compatible with one another

gandude

A good question.

A paper on 1234 touted it's strenth (the engineers), another paper questions the reasons for using it. seems the auto manufacturers get a kick-back for being 'green' in the form of points with CAFE standards.

http://www.motor.com/article.asp?article_ID=1758

sbagdon

Was reading that the gases are not cross-compatible, yet the tools are (so you'd have to maintain two sets of tools). Sniffers, vacuum pumps, gauges sets, everything should be re-usable, yet just don't cross-contaminate your tools.

Hearing that it'll be 10x as expensive, yet have 1/500th(?) the environmental impact.

Dirt Driver

Jeez, it's entangled with the Feds' enormous carbon credit sham.

iselloil

You don have to change the condenser to got to 134.DO a flush, change the dryer,vac it down and go with it.

Dirt Driver

I ask because my '94 has an R-12 system and I've seen others like it that did too.