Yes

 

And in what way would that change things, Greg?

Do you just not like the product or does it require a different oil?

 

If the label doesn't say "dichlorodifluoromethane" it ain't r-12. It may be a mixture; someone needs to read the label; if the mixture is r-12 plus "xxxxtane" like butane, it is flammable. I don't know the chemical name for butane, and I can't remember if Freeze-12 is flammable, but if it is I wouldn't use it. Some people swear by it, but they must have applied it to a clean system. Flammability is a separate issue. YMMV.

 

Using anything but R12 or R134a is opening up a huge can of worms. It may work for you or it may not. There are many issues with them, but I will list two common ones (apart from most of them being flammable):

- Most of these types of refrigerants are actually blends of R134a and something else. Since the fractions in these blends have different properties, in the event of a leak, one fraction may leak out first. At that point, you do not know exactly what is in the system anymore and many issues can arise. I.e. how good is the remaining refrigerant at carrying oil throughout the system?
- Hardly any A/C shop/tech is willing to work on such a system because of so many unknowns. Commercial A/C recovery and flushing systems are very expensive and quite sensitive, and can be completely ruined by the wrong refrigerant type.

That said, I really cannot understand why people would go with such refrigerants. They are mostly R134a anyway, and R134a is cheap and easy to convert to.

Dan
'91 928GT S/C 475hp/460lb.ft

 

Freeze-12 is a blend of 80% 134a (an HFC) and 20% 142b (an HCFC). No HCs in Freeze-12, so at least it's not flammable.

Being that you're only using $75 or less of refrigerant (even for R-12), I don't really understand the logic of going with anything other than R-12 or R-134a. Especially if you're flushing and starting over with new oil, why not go with the refrigerant that's compatible with everyone's service equipment?

 

We used to use it when R12 was not to be found, it works, but you can get R12, so use it.

IT does not work as well as R12 IMHO

Many compressor manufactures and rebuilders have tests to run on compressors and will not warranty any that have used Freeze 12 also.

 

Are you sure about the high-side pressures? 240-250 PSI sounds pretty high at 1200 rpm. It may be non-condensables (air in the system due to an insufficient vacuum) or blocked condenser fins which reduces overall heat-exchanger efficiency.

As somebody else here mentioned, the shop manual charging charts are spot on when charging the system. Keeping the vehicle's windows open also allows you to spend more time properly diagnosing and charging the system.

 

I'm no expert here but freeze-12 says it requires 10% less charge, if hi-side is too high could the system simply be overcharged? Although I +1 the idea of too much oil.

78 928 - I still run R12 when it runs.

 

Ay-yay-yay... so many confounding factors!!!! Thanks for all the great info, guys!

So I think the first thing to try is to recharge with a 90% by weight charge of Freeze-12 to see if it blows cold then. If it does, I will leave it at that (so I don't spend money just for fun) and put real R12 in one day down the road. If not, then on to...

Level 2: Remove compressor and drain, replace the drier, flush all refrigerant lines, and recharge. I will insist on R12 at that point.

I am just hoping I don't run into an incompatible-oils problem!