Improved R134A?

[Dave in Texas]

Back in 1998 I had to rebuild the AC system in my '87 Coupe DeVille, so I converted it to R134A. At the time I figured that eventually I'd also have to rebuild/convert the system in my '81 truck, so I bought 12 cans. Back then a can cost less than $2ea. Truck still is on R12 and soon after that, I 'came across' 6 cans of R12. Recently I was browsing in the auto dept of a major store and saw the price of R134A is now in the $7 range. The cans all read 'improved' on them. I still have 6 of the cans I bought and I'm asking what has been 'improved' in the formula of the new R134A? Does the original formula in the cans degrade over time? Just curious, thanks.

[BodybyFisher]

The price of 134a had skyrocketed, you are lucky to have a supply of it where you paid the old price. I understand that a factory was closed but I am not sure about that.

I have not heard how it or if it was improved

[zonie77]

I don't believe there is any change with time. The only concern is if there is a leak. They usually stay full for years.

I don't know anything about an improved formula. A lot of it now comes with an ounce of oil...might that be the improvement?

[The Fred]

I was talking to a mechanic a few years ago and he told me that 134a tears up compressors.. is that right, is it harder on the compressor?

The one I bought says that I can use R12 or 134a and I know for a fact that R12 cools just a whole lot better,

But how much is R12?

Also, back in about 2000 someone told me they'd be replacing 134 mid 2006 with some new one I don't remember the name of. When when?

[Ranger]

If R134a "tore up compressors" we'd all be replacing them. My '97 had 107K on it when I sold it and I never touched the A/C system. My wifes '96 Bonneville with 130K still has the OEM compressor. I think your "mechanic" needs to go back to A/C school.

I don't know if R12 cools any better than R134a or not, but I do know R12 is about $25/lb. and you cannot buy it. Only licenced shops can purchase it. You can get licenced pretty easy for a fee, but buy the time you do that and then buy it (probably in 25# tanks), you have saved notyhing.

I have not heard of any plans about changing from R134a. Sounds like another myth.

[KHE]

Sounds like a marketing gimmick to me... Always use plain R-134a - do not use any R-134a that has sealer or o-ring conditioner mixed in.

R-134a is slightly less efficient than R-12 but the HVAC components are designed to compensate. R-134a is not "harder" on compressors - at least not in systems that were designed for R-134a. Maybe some high mounted R4 compressors did not fare well with R-134a but all 1994-1995 GM full size trucks had the R4 compressor with R-134a... Vehicles retrofitted to R-134a are a whole different story...

You can find R-12 on ebay in 12oz. cans - sometimes at a good bargain but you need to have EPA-609 certification to buy it.

The Europeans are pushing for CO2 but at this time, there are no plans for domestic automakers to deviate from R-134a.

[The Fred]

I'm glad I asked over here.

[Dave in Texas]

Ok....thanks for the replies. The system always cooled great, but this year not as good. I'm thinking the orfice tube may have some obstruction, so I may take the system down and check that. The pressures are ok. I recall reading that the Ford tube may be a better choice? Also, when I do this, I intend to replace the accumulator. When I refit the system, I used a 'stock' accumulator. Is there a better choice for that piece?

I figured that 'improved formula' was b.s. I know not to buy the cans with sealer in it. Sealer is a band-aid quick fix and isn't good for the innards of the system. I appreciate the responses!

[BodybyFisher]

I dont know much about AC but I heard that you can replace the orifice tube with one that will cause the system to cool better, is this true?

[JasonA]

There is a variable orifice valve available, but when I had my A/C system done, I asked the question and KHE said that there's no real benefit and it can make diagnosing any problems more difficult (this makes sense).

[zonie77]

There is a variable orifice tube that's supposed to improve cooling but I have not used it.

R12 "carries" the oil through the system better than R134. If you run the R134 system low it will cause more compressor wear because the oil movement is reduced out of proportion to the reduction of freon.

"Why Keep the Correct Charge in the System? [Motor Magazine, Apr 03] A "just-low" R134 refrigerant charge (typically a 10% to 20% undercharge) significantly reduces oil flow, according to Four Seasons' Jim Johnson. He gave this example for 88 F ambient: The a/c duct temperature rose just 3 degrees (from 46 to 49F), hardly enough for a customer complaint. Yet so much oil was trapped in the evaporator under low-refrigerant conditions that oil circulation dropped from about 10% to 25% by weight to just 2% to 4%. That's a prescription for increased compressor wear and therefore short compressor life. Other causes of similarly low oil flow, he said, are internal restrictions (typically from contamination, which increases rapidly with low refrigerant), poor airflow through the condenser and high coolant temperatures."

[OynxSTS]

R12 "carries" the oil through the system better than R134. If you run the R134 system low it will cause more compressor wear because the oil movement is reduced out of proportion to the reduction of freon.

This is almost right. The issue is that there are specific oils for R12 and R134a and they are not compatible. If you switch from R12 to R134a you MUST (no ifs ands or buts) MUST replace the oil with an oil compatible with the new refrigerant. It's not the refrigerant that tears up the compressor it is the incompatibility of the oil and the refrigerant.

Most conversions don't do this and a year or two later you have to buy a new compressor... BTW when the compressor "goes" it usually fills the entire system (except the evaporator) with ground aluminum requiring most of the components to be flushed or replaced. $$$

IMO Most R134a conversions... suck... To work right, factory R134a systems run at a higher pressures and use different types of O rings and fittings to deal with some of the other issues that R134a systems have. Honestly, to convert to R134a you really need to replace the oil, the pressure switch, all of the O-rings, the orifice, and sometimes the hoses too (Not on GM cars though)

R134a molecule are tiny compared to R12 and the system needs to be "perfect" if it is going to hold a charge for any time... If you have an R12 system.. bite the bullet and stick with R12. In most parts of the states you can still get it...

In Canada and elsewhere in the world R12 is a bit of a challenge. Some people believe it or not have switched to Propane as a refrigerant. It is cheap, works with R12 Oil and all of the fittings and runs at lower pressures... Except for the fact that it Goes "KABOOM" it is a perfect refrigerant!