I'm going to try using Freeze12 in my 964. I've been reading up on the forums, and realise that the use of Freeze12 is a bit controversial (there were several heated(!) exchanges on the forum a year or so ago), but have decided to give it a try anyway - there's not much to lose.

I had the system recharged with R12 last Summer, and checked for leaks. The PO had told me that there was a slow leak, as he found that he needed to recharge the system every year.

Sure enough, despite the shop not finding any leaks, my A/C is blowing hot again (it was blowing low 40s after the refill).

So I have bought a Freeze12 kit on Ebay. The kit includes three cans of Freeze12, one can of "Oil Charge", one can of "Leak Stop", a check gauge (looks like a tire pressure gauge), and a "quick charge kit" containing a red schrader valve, a blue schrader valve, a dispensing valve, and a short connecting hose for attaching cans to the valve.

My plan is to first check the A/C pressure using the check gauge on the low pressure side of the system. First question: where is the low pressure valve?

I'm expecting it to read low. At that point I suppose I need to replace the existing schrader valves. Second question: what precautions do I need to take before replacing the valves?

With the valves replaced, I will add Freeze12. Third question: should I add the oil and the leak stop before or after adding Freeze12, or doesn't it matter? Should I put in a whole can and then check the pressure, or should I check the pressure more frequently?

 

Freeze-12 is "drop-in" replacement. It should use the R-12 fittings. Good luck with the swap-over. It should work fine until you finally decide to replace the leaking compressor and then you should go to R-134a.

 

Thanks ... I'll check the fittings on the vehicle and compare. I was looking at the EPA website, and was confused about their claim that there is no such thing as a "drop-in" replacement ...

 

Julian, I did this last year but I was able to use the old R-12. My Dad bought a case of it back in 93 before he died. anyway... I replaced the receiver/dryer... replaced the schrader valves and put a vacuum on the system for almost an hour as I recall. I pumped it full of R-12 using a gauge set off of ebay and it was cooling down extremely well. I was wondering if it would make it through to this year... YES! I cranked it on a few days ago and it's still very cold! (Having the fingers crossed DID work!) Pulling the vacuum is VERY important especially if you swap the schrader valves. (You introduce moisture into the system!) Pelican sells a kit that has all the o-rings and valves you need to replace everything. You might want to consider replacing the receiver/dryer... It is very inexpensive ($50 I think) and will help to keep things cold!

Ideally you should take the car to a place that can recover the gas in your system. Mine was completely flat so I didn't have to worry about anything. If you want to know if you are pressurized you can either hook a gauge set up to it or take a small screwdriver and briefly push in on the schrader valve. Then you'll know if the system is still pressurized or not.

Do yourself a favor and buy a gauge set. They are cheap insurance against over or under-filling.

Good luck and post back how it goes!

 

Hi Smokin,

Great input: thanks! I need to check the connectors I got with the Freeze 12 kit to see if they match the valves on my R12 system ... I suspect they don't.

I'll post an update when I've checked the pressure, but I think it's flat, judging by the complete lack of cold air coming through.

When filling, do you do that with the engine running, and the A/C on full? Did you add oil or leak stop?

 

smokin howed you pull a vacuum through, did you do all that your self or hire someone???


JERRY

 

Julian... I'll bet you have the R-12 connectors but a quick check will tell... You apply vacuum with the system off. (I did anyway.) Your compressor won't run with no pressure in the system. I used a vacuum pump like this...



while using gauges like this...



I bought my gauges from ebay but Harbor Freight has them much cheaper. You don't need a $300 gauge set for this. I did buy the vacuum pump from HF though. I have a 60 gallon compressor in my basement so I just strung out the compressor line up to my driveway. I held just under 30 inches of vacuum for about 45 minutes wich is more than enough time to boil away any remaining moisture in the system. (Engine off) Prior to that I swapped out the schrader valves and a few o-rings that were very easy to get to. I did not add any oil to the system. I figured that after 17 years it had more than enough already in the system. I also did NOT add stop leak. I figured if it had leaks I would track them down and repair the system, not just mask the leak. After pulling the vacuum I started the car, put the A/C on full blast and filled the system. It took 3 cans of R12. Changing the seals must have worked because it's still ice cold this year. I actually had to turn the A/C DOWN today... It was getting too cold! It's very easy to do and the investment in tools pays for itself! I researched it on the Internet since I had never done this before using a set of gauges.

Give it a try... You'll be glad you did!

 

I live in Atlanta and own a vacuum pump if you want to evacuate your system. Free as long as you bring the lady in the picture! Seriously, if you want some help, send a PM. I only have R-12 fittings and so far mine is holding its R-12 charge three years in a row.

 

OK Smokin ... thanks for the encouragement!

The Quick Charge Kit contains two schrader valves which actually screw onto the existing R12 valves on the compressor. The new valves are Red and Blue, and different sizes, so no danger of attaching the wrong way :-)

I haven't actually attached anything yet: still researching the right procedure. There's a useful page here: http://members.tripod.com/~jbabs714/autoac.htm which cleared up a lot for me.

Julian

 

I believe the gauges shown above have connectors for both R-12 and R-134a (Mine does) so the gauges will work either way. The vacuum pump too.

 

Wow thanks for the offer springer, PM sent

JERRY

 

I have converted 7 systems to Freeze 12. 6 had subsequent compressor failures. The last one I added 134 oil to the existing system and the system is still operating 4 years later. The car and compressor has 140 miles on it now, with about 70,000 with Freeze 12. I consider the 134 oil a must. Freeze 12 is a blend of 80% 134 and 20% 142.
The Freeze 12 cooling is better than 134 but not as good as old 12 at lower speeds. The pressures are lower than 134.

If you are retrofitting a system, use the largest modern condensor possible. Even two in series. You can't have too large a condensor, this will improve your low rpm cooling abilities. Be sure that your fan clutch is new. Check voltage to electric fans to be sure they are running at maximum rpm. Go from a 5 blade to a 7 blade with HD fan clutch if necessary. BTDT.

Duracool works better but is now illegal in the USA.

Here is a valuable site for pertenant information. Browse the pages.

This site won't allow me to post a link so go to the EPA site as follows....
epa.gov/Ozone/snap/refrigerants/macssubs.html

 

The law requires 134 type fittings on a Freeze 12 system and the appropriate label indicating Freeze12 and when/who did the conversion.

Freeze 12 is azeotropic (sp?) meaning that if you develop a leak, you shouldn't just add more, but reinstall a totally new batch. (If it leaks, its blend proportions change since one leaks easier than the other.)

 

Thanks for the excellent advice. I will add the oil that was supplied with my kit: I was in two minds before.

The Freeze 12 kit has a pair of schrader R134 valves that screw over the existing R12 fittings. What puzzles me about this set up is that unless the R134 fittings depress the R12 valves, then there will be two valves in series ...

The kit also included a pressure gauge, like a tire gauge. The business end of this gauge is a nozzle-like protrusion that has two small holes in the tip. I do not understand how to use this gauge, since it does not match the opening in the R134 fitting. Very odd.

 

I had some inteference fit on my 134 fittings, so I removed the inserts in the base fitttings.