jleidel

Has anyone tried one of the r-12 refrigerant replacements on the market? I've seen quite a few marketed on other various car forums/websites. Several even quote the ability to act as a drop in replacement, w/o retrofitting. Specifically, Freeze-12 from Johnson's Chemicals make this claim. [even though legally you must completely remove all the current refrigerant before you charge the system with something different].

Thoughts?

http://www.freeze12.com/
http://www.aa1car.com/library/tr497.htm

dr bob

Are you the caretaker of the refrigeration forever more in the life of this car? Did you fix the leak(s) that caused the recharge need? Generally, by the time all the leaky o-rings and seals are replaced and the drier is changed, the only difference between the marginal replacements and mainstream R-134a is changing the compressor oil out for POE. M<y too sense.

IIRC, your local 928 parts supplier knows where there is R-12 available too.

jleidel

The seals and o-rings will be changed. I didn't plan on swapping the receiver/drier unit.... hence the question.

I'm certainly not opposed to migrating to R-134a. I see 928gt carries both an OEM Porsche receive/drier and the URO equivalent. Are there any deltas [except price]?

928 at last

I've used the DuraCool in my GM products for years now with very good results. I really wouldn't consider using it in my car......
I don't care if a '95 Suburban or Jimmy goes up in flames, but the Porsche
The compounds are very similar to Butane (the stuff in yer bic lighter), so if there's a leak, and no airflow, and a loose plug cap......

WallyP

As a general rule, a commercial A/C shop won't touch a system with anything other than R-12 or R-134a.

R-134a is $7 a can at Walmart and $5 a can at our local Big Lots...

blown 87

Freeze 12 is not flammable by itself, but like R12 and 134 when mixed with oil under pressure it is.

joejoe

I have used autofrost in mine with no problems (decided to use this rather than r12 for finding a leak). It is a blend, that actually seemes to work better than r12 and can be added to r12. Head pressure was less and seemed much colder. Also as stated above shops will not evacuate a 'compromised system'. Luckily I have all equipment to do mine. I have since cleared system and am now with r12 after replacing bad condensor. I used this product for 3 years with no problem.

blown 87

Almost all of the customers cars I work on that have any kind of blend in come back in a very short while with nothing in them, bad luck i guess that all those schrader valves get loose.

dr bob

Specialists carries the 944 drier, a functional replacement for the 928 drier. It's a fraction taller and a fraction smaller diameter, so a shim at the clamp and a few inches of plastic spiral cable wrap around the PS cooler piping underneath will be needed. It's relatively inexpensive, has the correct dessicant for R-134a, and has s sight glass that may help with diagnosis if the system underperforms. Replacing the drier is a must i the system is open to atmosphere or the refrigerant and oil are changed.


My 10yo R-134a conversion in my S4 will freeze fingers on the wheel. With freeze switch jumped, it cranks 18ºF air at the center vent at freeway cruise speeds, 90+ ambients, fan on 2, black car with no tint in L.A. area. Driving today, the outside temp display said as high as 109º in Pasadena and over into the SF valley. I think it only got to 104º officially though. RH less than 50%, fresh air vent cycling with cabin slider set at 72º. While there's no simple cure for a heat-soaked car, the system certainly has the capability needed for my driving pattern here. Don't be afraid of a good conversion.

jleidel

All, thanks for notes. Dr bob, if you're getting that sort of performance in a similar climate, then I'm sold. A working ac is a must have around here for 7 months out of the year

dr bob

I'm not guaranteeing that all other conversions will give the same results I get. Justletting you know that the system performance is available. You have much higher humidity for instance. Yesterday it was about 40% RH at 98F, so dew point was probably in the mid 50 degree range. The system has to work a lot harder to drop temps below dew point of the air in the evaporator. For many systems this might be the lowest available evap temp. It will get colder in recirc mode as moisture in the cabin air is removed. Don't open any windows, and try not to exhale!

jleidel

yup... lived in DFW nearly my entire life. The humidity here can completely destroy the cooling capability of well-worn HVAC systems [home and auto]. I'm not after the 'meat locker' effect, but rather a comfortable environment on the most stifling days. Always glad to hear your advice Bob!

JHowell37

The receiver/drier is a service part and should be changed if it's more than a few years old. You should also replace the expansion valve.

soontobered84

John,
If you are replacing the O rings anyway, you really should replace the drier. Especially since there is an O ring on either side of it. From that point, you just need to unbolt it from the coil

jleidel

Sounds good... might be something else I add to the upcoming tech session [if time permits]