Compressor Seized, go to R134a or keep R12? - Page 2 - PeachParts Mercedes-Benz Forum

rorypff · #16 06-13-2007, 03:58 AM

I am aware that the R12 system should use the "Green High Pressure" cut off switch which closes at 20 bars and opens at 15 bars, but could some one enlighten me as to what the operating pressures are for the "Red High Pressure" switch which is supposedly to be used with R134a.

Thankyou

jcyuhn · #17 06-13-2007, 10:28 AM

Quote:

Originally Posted by jbaj007

R134a runs at higher pressures than R12.

Polyalkyl glycol lubricants can have a problem with chloride compounds such as CFC's and HCFC's. Any residual chloride left in a system has the potential of reacting with the PAG. R12, R22 are examples of these. There are DOUBLE END CAPPED PAG lubricants (Daphne is one brand, Japanese, I think) that many say will work with R12, but I would not use the plain old PAG. Double end capped referrs to the fact that the reactive ends of the Pglycol molecule are chemically "capped" to prevent halide (perhaps many anion) reactions.

Some would respectfully disagree with using ANY PAG with R12. I'm one.

Me too. I have consistently read over the last 15 years that chlorides destroy PAG lubricants. I was tempted to ask whether the original poster was recommending double end capped PAG specifically, but didn't care enough to drag the conversation there.

My view- R12 + PAG =

- JimY

Gil · #18 06-17-2007, 06:50 PM

I was never into the idea of a conversion, since most people say the 123 doesn't respond well to R134, but from everything I've heard, R134 not only doesn't cool as well, it also runs at higher, not lower pressures. This can't be good for a 20+ year old system designed to run at lower pressures. Just my .02

PS: Also, the new compressors produced for the 123 series have a different switch setup on them; some kind of an upgrade, I don't know more about it. Not sure if this will be the same in your case.

slk230red · #19 06-17-2007, 09:24 PM

I bought a Nippon Compressor, a new receiver/drier, expansion valve and new schrader valves. Installed all of the new components, vacuumed the system and charged with R12. The W201 only takes 2.2 lbs of R12. After completing the job, I discovered that the belt tensioner must have broken when the compressor seized, so I installed a new tensioner and belt.
Everything is working good so far.

Thanks for all of the advice.

Dave

PerkHouse · #20 06-19-2007, 11:23 AM

Quote:

Originally Posted by slk230red

...charged with R12.

Dave, where'd you get the R12? I'm just asking because if you bought it over-the-counter, it wasn't R12 - it was probably an R134 blend. If you went to a small shop and had them charge it, it probably isn't R12 either. It's probably an R134 blend. If it wasn't a LOT more expensive than R134, it probably is not R12.

In any case, I'm sure it's cooling. And maybe that's all you care about. But I'd make absolutely sure that it IS, in fact, R12 if that's what you want.

brewtoo · #21 06-19-2007, 02:24 PM

What do you mean by that?

If I buy a drum or a can that is labeled R-12, I think it IS R-12.

To be selling blends labeled as R-12 would wreak havoc with every recycling machine in the country.

If he bought R-12 over-the counter it's probably not R-12?

I'm going to have to call that nonsense.

PerkHouse · #22 06-19-2007, 02:44 PM

I guess I should've qualified my statement by saying that unless he's licensed, he cannot purchase R-12 himself. If (as an unlicensed person) he did buy something over the counter that he thought was R-12, it was probably in fact Freeze-12 or some other "drop-in" blend. Even if he took it to a low-volume shop, chances are they don't have real R-12 either and used Freeze-12 or some other "drop-in" blend. Hence, the reason I asked:

Quote:

where'd you get the R-12?

Care to retract your criticism?

300B · #23 06-19-2007, 03:26 PM

A 93 should already have 134a in it already.

E150GT · #24 06-19-2007, 06:00 PM

On Saturday I walked in to O'reilleys and purchased R-12 over the counter. Showed em my licence and bam. 35 dollars a can though

slk230red · #25 06-19-2007, 06:02 PM

Quote:

Originally Posted by 300B

A 93 should already have 134a in it already.

'93 190E's came from the factory with R12 and I'm the original owner and the only person that has worked on this car, other than a couple of warranty issues...mostly interior related.
YES! YES! AND YES!...I charged the system using a 30lb jug of R12. I've been working on cars for 40 years and when the R12 issues started many years ago, I stocked up so I wouldn't be at the mercy of Bubba at the A/C repair shop.
I can get a license and buy R12, but I don't need any at this time.

Dave

Speaking of R12...Remember when this stuff was everywhere and on sale for 99cents and sometimes less?