944Time

I have a R134a converted system. Not blowing cold right now, I think it needs a little hit of the R134a.

I am considering switching over to R152a.
R152a is commonly sold as air duster.


Refrigerant?


But not sure if it works better then R134a, at least in a system originally designed for R12.

Has anyone switched from R134a to R152a?

If so, cooling performance Improved, same, or worse? The price is about the same. Duster is maybe a little cheaper.

jhowell371

My S2 has been converted to R134A and cools just fine. I think I would stick with a proven product, R134A. YMMV

Flinched

Rob Siegel’s “Just Needs A Recharge” is a really good reference point for all things vintage AC. He gives a detailed analysis of the various chemicals available today with their pros and cons. (No affiliation other than I’ve met him at The Vintage a few times)

jhowell371

Hi Flinched. What is "The Vintage" event? Is it held near Baltimore/DC/NOVA

Flinched

Sorry, BMW reference there. The Vintage is an annual event held in Hot Springs, NC for BMWs from the early 90's back. Usually draws about 6-800 cars. Rob drives down from Ma. every year and is very knowledgable and approachable. The information in his book applies to most European cars pre-auto electronic climate control days - so our cars.

V2Rocket

i guess you could but my mind always goes to the middle of nowhere roadtrip scenario.
youre driving in west Texas in July and you notice your AC isn't as cool as it should be. old hoses its probably leaking out.

you can pull into any auto store, walmart, etc and get a can with a gauge/hose tap of R134a...can you get the alternative off the shelf?

or will you be aiming air dusters at your low pressure port

Jfrahm

I've used R152A with good effect in my 968 and need to get some in there now. I had a very slow leak that took forever to find and kept losing half my gas. With AC dye and a lot of patience I finally found a pinhole in the condenser last winter. I only have my leak testing gas in the system now (propane) but it's held pressure long enough to warrant putting the R152A in, or maybe half and half as propane works well also.

The only problems I had with R152A in the duster cans was getting a good seal on the can tapper and accidentally getting the bitterant on me and later in my beer. I think this was from the pop when removing the manifold lines. That stuff is bitter!
For the can tapper issue I rigged up an adapter from the spray head to a recharge line, it does not flow much but you can save the unused gas in the can for months.

-Joel.

bureau13

Is 152a supposed to be better in some way? I'm not clear on why you would go this route rather than 134a, which is not particularly expensive and available everywhere.I know for a while on my 928 that was converted to 134a, I was convinced that was the reason cooling performance was sub-par, and considered trying an alternative. Turns out, that was not the reason, and it's working fine now.

My 931 is still R12, so I can't comment on that directly, but I see no reason it should be any different...

Jfrahm

It's supposed to be better, more efficient than R134a and compatible with mineral oil,which is already in my R12 system.

bureau13

Interesting...there have been a number of these alternative refrigerants over the years making this claim. I messed around with one of them (R406a maybe? I might have that wrong) briefly at one point. One issue with a lot of them is flammability, which I believe is the case with R152a. Obviously not an issue if everything is working properly and there are no accidents, but is an additional factor to consider.

Jfrahm

If it's that flammable would people use it for a dust spray? The AC oil is also flammable, I do not worry about the small amount of refrigerant in the system causing a mushroom cloud in an accident.
I'm generally not a fan of R134A, so far I like this alternative.

bureau13

Well, it's a factor to consider. If it doesn't matter to you, feel free. It is definitely more flammable than R-134a or R-12, like most of the other alternative refrigerants I've seen, which is a factor that should at least be considered when weighing one's options.

tempest411

This is very interesting considering I haven't been able to find anything but good reports from using it. Haven't found a single downside about it. Regarding it's flammability, it would have to be under uniwue circumstances because if you spray the stuff into a hot torch it extinguishes the flame! This begs to ask the question; why are they using the stuff to blow off keyboards as opposed to just selling people a can of compressed air?

Jfrahm

Phase change. If you have ever used a SCUBA tank you see at 3000 psi air is still a gas and the tank is very heavy and strong to hold a decent amount of air. Refrigerants and propane turn to liquid at around 80-100 psi so you can put a lot of it into a can that only has to hold 100 psi.

To use the same can with just air you would only have about 6x the volume of the can in gas to spray on stuff. If instead you use one of these materials that turn to a liquid, the liquid expands almost 300 times when it turns to a gas. You probably have 200x the volume of the can in spray. Compressed air in that same duster can would go "psst" and be done, like airing down a road bike tire.

Perry 951

Because the volume of compressed air, in a spray can at a safe pressure, is minuscule in comparison to liquefied difluoroethane.

As someone who is ASE A7 Certified (Auto HVAC) and has a 609 Exemption to work on these things leagally, I cannot imagine anyone seeing a benefit of using R152A over R134A in a system that is designed for R12 or R134A. You can't get bulk R152A; you'll have to rig up some contraption to charge the system, and then when you need to recover it, you'll have to vent it to the atmosphere as there are no approved recovery devices for it. If you're a big enough jerk, you could have a shop recover it without telling them, and then they end up with a poisoned piece of equipment (if it is older and does not have a detector).

I can get nearly any sealed system with good components and airflow to perform as good as when they were new. Here's some hints:
1. Make sure you have proper airflow through the condenser and evaporator. On these older cars, you'd be amazed how much crap is stuck in the inlet of the evaporator. Reduced airflow means increased heat retention by the system.
2. Make sure you have the correct oil and amount in the system for the refrigerant you are running. If converting from R12 to R134A, take the time to fully flush the system. This includes the compressor. Shortcuts reduce the system capacity and increase heat retention.
3. Make sure you fully evacuate the system. A quick vacuum won't do it.
4. Make sure you properly charge the system by weight. If converting, make sure you look up a conversion chart to get the proper charge weight. I don't care who you are or how good you think you are with reading pressure gauges, you won't get it right unless the right amount of refrigerant is in the system.
5. Pay the money for a shop to recharge the system and ditch the suicide cans. My little 5 bay shop sees an average of 50 vehicles a year that are grossly overcharged due to use of DIY recharge cans. The low side of a good system will stay "in the green" well beyond it's high pressure overlimit. If you insist on doing it yourself and want to use system pressures, get high side gauge and a reasonably accurate thermometer.

AC service isn't (or shouldn't be) that much money at a good shop. A suicide can is $40 in my area; about 1/2 the going rate for a recover and recharge.

And in case you wonder why us technicians call them "suicide cans".. some people back in the R12 days would try and charge the system through the high side by accident or by thinking they can force more liquid in. They would blow up the can, blow up the compressor, or blow up the lines and get hurt. The potential of overcharging a system with the DIY cans can cause the lines to rupture, and God forbid, rupture right by where your hand is when it goes.

400PSI will tear flesh off the bone... but the frostbite won't hurt as bad.