A/C lines for R134a

[nmlss2006]

I am looking to REINSTALL A/C in one of my cars, a 325iA 02/91 build that currently has a somewhat different engine in it. The PO removed the A/C bits from the engine bay, so I am looking for the lines and pieces, the car only has the stuff inside the cabin up to parts 6/7 where they poke through the firewall (there is a parts wanted post about it).

http://www.realoem.com/bmw/showparts.do?model=1123&mospid=47309&btnr=64_0529&hg=64&fg=60

The next question becomes: there seem to be R12 lines and R-134a lines. However, to the best of my knowledge, in any E30 MY88+ the only concerns are the dryer, the compressor, the regulating valve and possibly the condenser, NOT the rest of the stuff, that is, any installed lines should work. Can anyone shed any light? Of course I'll run R-134a.

[blocke]

I dont think the lines matter at all. Lines are lines. The only difference is the low side and high side fittings, and you can get adapter kits for those. Its the compressor and condenser that are important. Theres supposed to be some oil that you put into the system that keeps your seals and everything from rotting, then you fill the refridgerant.

[e30Matt]

blocke is right. The lines are identical, however you will want to pick up an A/C seal kit that contains O-rings and gaskets that are made for R134a, as the refrigerant will react with R12/Ester O-rings and eat them alive. They're easy to spot, they're green in color instead of black.

[nmlss2006]

That's what I figured. The amount of mineral oil which remains in the rubber of the lines should not be an issue, I hope.

[nmlss2006]

Thank you Matt: now the question is - where do I find the kits? I could not find them on realoem or Pelican...

[blueapplesoda]

Just to let you guys know that r12 hose and r134 hose is not the same. the actual rubber hose sections that are designed for r12 will allow r134 to leak by means of permeation because the r134 molecule is smaller than the r12 molecule. That is why hoses must be replaced sometimes.

FYI It will work, I'm just saying every once in awhile you'll need a can of 134 to recharge your system.

[nmlss2006]

BAS, thanks: the problem is, BMW *does not make* one of the hoses in R-134a form... therein lies the problem.

[RedTRex]

You should change the expansion valve as well....it's under the right side of the console on the side of the evaporator.

[Turf1600]

BAS, thanks: the problem is, BMW *does not make* one of the hoses in R-134a form... therein lies the problem.

All lines in 88+ are already 134a compatible.

[DJB]

All lines in 88+ are already 134a compatible.

I do not believe that any of the factory lines are barrier hoses. They are traditional fiber reinforced rubber hoses with barbed fittings.

One way to tell is when the hoses leak. Traditional hoses have subtle pinholes pierced through the outer layer just to the fiber reinforcement so that refrigerant diffusing through the hose doesn't cause a bubble to build up at that point, causing de-lamination. Barrier hoses have less diffusion, and there are no pinholes.

Replacement hoses are made with barrier hose, and have been for a long time. But it has apparently taken much longer to use up the old stock of pre-1988 hoses made with traditional hoses. And new parts aren't made while the old stock is still in the warehouse. About two years ago a few sites had the R12 hoses on sale, just when they started selling barrier hose assemblies. (The exception was the commonly replaced compress-to-condenser hose, which has been available only as a barrier hose since the 1990s.)

Using the "R12 hoses" is not much of a problem except for their age. More refrigerant will diffuse through, but it's not a significant problem unless you are using a refrigerant blend. With a blend, the proportions will change as the smaller molecules diffuse faster.

Specifically, neither R134a nor the common lubricants will destroy the hoses or nitrile/NBR o-rings. The problem with R134a is that it will harden Viton seals and o-rings. However Viton was (is) expensive and was only used in the most demanding high temperature sections -- inside the compressor and the o-rings at the compressor manifold.

That said, old hoses are more likely to be a little leaky, and their usable lifetime is likely to be less than barrier hoses made with higher tech materials.

[nmlss2006]

Coming back to this thread - so what you're telling me, DJB, is that if I were to go to Blunt or Tischer or some other high-volume BMW parts supplier and order BMW parts for the hoses, I should get barrier hose despite what the TIS/ETC says? The reason I ask is because if that is not the case I'll buy a Mastercool 71550 and start crimping. God knows it will be cheaper anyways.

[Jean]

It would probably be cheaper still to have a local a/c shop make a few lines too.

All the muscle car/classic cars that get a/c work / line done do it all the time.

[nmlss2006]

Jean I'd readily agree ... if I knew where a local A/C shop was :).