Jump to content

Recommended Posts

This was posted on a informational site for the U.S. automotive aftermarket industry. The article stated that the refrigerant that will be allowed in new units after Jan. 2016. The one that is used in Europe will replace the 134a.

The propellent currently used in the flat tire repair cans is based on the 134a.

I will try to find more info. and a link to the article.

Link to post
Share on other sites

Try www.allpar.com/eek/ac.html . I found that via Google and it's a decent discussion of R134a and 1234yf, plus some comments about changing from R-12 to R134a Freon.

Here's my suspicion about changing from R134a to the newer 1234yf refrigerant . . . I found a forum discussion on www.ackits.com back in the earlier 2000s. It was about changing from R-12 to R-134a AND getting the same cooling results. Key thing in this discussion was that GM POA valves ARE adjustable, just that GM never advocated that (for warranty purposes and reasons), yet Ford did (for the vehicles they built that had the GM POA valve in them). Key thing is that when evap pressures are taken with the a/c blower unplugged and the a/c system operating, the optimum pressure is about 29psi for R-12. For R-134a it's 26.5psi.

With the POA removed from the lines, there's an adjustment "nut" on the internal valve. This would be what's adjusted on the assembly line when the valve was built. Turning the adjustment nut 1/2 turn CCW should lower the pressure from 29 to 26.5, which puts the gas pressures back into the same relationship as if the system had R-12 in it. Same 40 degree vent temps, too. The SAME adjustment works with all GM "gas valves" and the Chrysler EPR valve, too. GM's VIR system contains a mini-POA valve which can also be adjusted, just need a gasket kit to take the VIR portion of the accum/dryer apart and put it back together, from what I can find.

From what I've seen of the new GM systems with1234yf, they take less gas than R-134a did. I haven't researched the situation just yet, but I suspect that an adjustment of low side pressures should get the cooling back to where it used to be.

Used to be that there were THREE a/c system oils, for motor vehicles. Now, there are "universal synthetic" oils that should make life easier.

On the GM CCOT systems (cycling clutch orifice tube), the pressure switch is the key to cooling performance, just as the orifice tube might. On some of the later '70s systems, there is an adjusting screw . . . which purportedly needs a full turn CCW to lower the evap pressure.

Key thing is that if an "oil change"/purge is all that's really needed, then it can be done "anywhere". Plus changing the pressure switch to one with the correct working pressures for 1234yf, should get things decently cool in the car Upsized condensers can be a help, too, as can an electric assist fan. Fresh oil, new cycling switch, and new gas should be "the deal" . . . especially with "legal" Freon types.

Just some thoughts,


Link to post
Share on other sites

The reasonable industry perspective: http://www.vehicleservicepros.com/press_release/11309002/epa-to-propose-eliminating-use-of-r-134a-refrigerant-in-vehicles

The reasonable scientific perspective: http://www.washingtonpost.com/national/health-science/obama-targets-a-popular-coolant-in-new-effort-to-curb-greenhouse-gases/2014/09/15/cd24c738-3d18-11e4-9587-5dafd96295f0_story.html

The "Oh for the love of God stop the Democrats!" perspective: http://investmentwatchblog.com/obamas-epa-to-ban-r134a-most-common-refrigerant-used-today/

BTW, those "Fix-a-Flat" cans are never recommended for cars that have TPS systems. The sealant ruins the sensors, to the tune of $150.00+.

Link to post
Share on other sites
  • 1 year later...

BEST to get the canisters rather than the "cans".  On the LAST day that R12 could be purchased, I bought some to go with the cans I'd already bought.  As the 16oz cans initially had a full 16 oz of gas in them, then 12 oz, and 10oz I the SAME cans.  At that time, I didn't really know where things were going to be, regarding "other" gas to replace the R12.  I put those 6-can cases under my carport.  A  few years later, when doing some moving of things, I discovered that over 1/2 of the cans were empty.  Some still had some gas, but others didn't.  Leaked out of the crimped caps on the cans, which is allegedly ONE reason the cans were discontinued . . . . too much gas lost in that capping process, plus the later leaks.



Link to post
Share on other sites

Read the articles.  The ban is on the use of R134a in new vehicles.  Unlike the R12 ban, the current legislation does not limit the production or use of R134a for repair of existing systems.  I've retrofitted a number of R12 systems to use R134a.  These were all GM CCOT systems and all I did was flush the system, replace the dryer, orifice tube, compressor, and o-rings.  Cooling in the swamp that is northern VA in the summer has been fine.

Link to post
Share on other sites
  • 4 weeks later...

Never had a problem converting r12 to 134a and never had anyone prove to me that their a/c wasnt as cold anymore


Thing is, 134a is slightly less efficient a refrigerant than r12 and it will take longer to get down to the temperature the thermostat (or thermistor ) is set at


That time difference is about 5% longer :)


Thermostats control the ultimate temperature that the system is designed to work at and provided the gas thats in the system and the system itself is capable of getting to the set temperature, it will


I havnt come across the 1234yf stuff yet, but it is only a matter of time


From memory (I did this 6 months or so ago) the last price I got for an 11 kg bottle of the 1234yf was around $1500AU, might have come down a little now but at that sort of price and the very small volume of vehicles I will see with it, I think it will only be done by dealers/manufacturers for a while yet here


It is a business opportunity I guess, to buy it and advertise that I have it, but maybe later :)


Sorry for the edits, but just for information's sake, here in Australia, you have to be licensed to handle and store 134a (as well as most other refrigerants), but not this 1234yf, anyone can buy it here



Edited by Ttotired (see edit history)
Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
  • Create New...