Has anyone had any experience with the alternative refrigerants currently advertised that are said to be suitable to replace R-12 without needing a license to purchase? Supposedly, these are "hydrocarbon refrigerants," and they come in the little cans that we used to use to replenish our R-12 systems. Also, has anyone had any success with AC stop leak products? I have a 1979 300TD that seems to have trouble holding a charge. Much thanks for your input.

Without going into the details, the best alternative refrigerant, I think, is the R134a. If you want to know more about it, the internet is a good place to start. Some web sites list many alternative refrigerants and their composition, test results, etc. Each refrigerant has its own problems and restrictions. After all the readings, I decide to use R134A for now until something better comes up.

David

Joe,

The R134a conversion is the way to go. There are several debate topics on R134a here, if you do a search.

You will here a lot of Opinionated suggestions :rolleyes: on how to convert by changing compressors, the oil is not compatible...bla bla bla
In the 100+ cars I have done, I used the kit from Autozone, Discount and Walmart now carries it! Work just fine follow with no long term problems. Just follow the directions and enjoy cool A/C ;)
Regards,
Bryan

134 a causes testicular cancer. it can kill you in five minutes if your evaporator under the dash leaks and you breath the invisible odor-free fumes. at one time i lived in al. and they sell duracool, a ozone friendly, non-toxic, r-12 compatible product. i used it in my 83 240d when it was a little week on the cold air. I ran the car for four years after the recharge with no bad side effects. air temp would go as low as 28 degrees. mark

I would search the archives to come to a selection on this, and then check your local regs. Every shop and MB dealer I checked in SoCal told me they could not get R12 to recharge my system, and only R134a was allowed per AQMD, Cal EPA, etc.


Regarding duracool, I knew that it was not a legal product in our area, so I decided to research the reasons why. I discovered the following:

1. per the EPA http://www.epa.gov/ozone/title6/snap/hc-12a.html#q1 Duracool 12a is not legal. "It is illegal to use hydrocarbon refrigerants like HC-12a® and DURACOOL 12a® as substitutes for CFC-12 in automobile or truck air conditioning under any circumstances."
2. Duracool is hydrocarbon based, and flammable or explosive, depending on how it is used or released.
3. ANY coolant released into your car has the potential for killing you due to displacement of the cabin air, assuming you have the AC set to recirculate, and enough oxygen is displaced. Even pure nitrogen gas (which makes up over 70% of the air we breath), will kill you if it displaces the air in a confined area.
4. Unexploded or uncombusted Hydrocarbons are not generally thought to cause greenhouse effect or ozone depletion (although there is a growing body of evidence showing propane and methane as greenhouse gases). Hydrocarbons DO create photochemical smog - the brown stuff you see.
5. The only medical statement I found stating that r134a was carcinogenic was listed on a site that sold Duracool/r12a type products. No Material Safety Data Sheet, EPA, or NIOSH document which I examined listed cancer as a side effect for r134a. In fact, the MSDS documents assert that r134a tests negative for carcinogenesis by 3 different protocols. Side effects listed were frostbite and skin absorption/inhalation hazard (with potential for cardiac arrhythmia).

The EPA site above and the abbreviated site below list EPA approved (Although maybe not locally approved) refrigerants and their compositions, as well as compressor warranty info, etc. Please note that the EPA does not test for cooling efficiency, or long term mechanical friendliness to your AC system, just the health, safety, and clean air aspects of refrigerants.

http://www.hrmcomp.com/newprod.htm

Hope this info helps.

[Edited by JCE on 06-08-2001 at 06:30 PM]

I saw it from news TV. A car blew up and caught fire when the owner turned the ignition key to start the engine. The owner got burned but he was okay. Flammable gas was leaking into the passenger compartment.

David

What I heard So far...
 

First, JCE's links are quite awesome.

I have been told to stick with R-12, and buy it on ebay if you have to, because the older systems were not designed to handle the pressures of R-134a refrigerant.

I have been told that "Freeze 12" will adequately and directly replace R-12 refrigerant, and that it will cool as well as R-12, and I have been told by others that it won't work as well, and will still blow out your compressor in short order. Freeze-12 is 80% R-134a & 20% R-142b...

I have been told that R-134a is the right replacement, and I have been told that R-134a will result in a compressor replacement in about 6 mos. Some swear by the R-134a conversion, but then add that it doesn't cool as well as the original.They say that it works well at highway speeds, but sucks at slower speed like when in traffic, or downtown...

The secret seems to be in lubricating the compressor, and the pressures exerted on your AC system.

I ain't decided yet, so let me know what you come up with...

R-134A
 

Brothers of The Benz
I think R-134A will replace Synthetic Oil, Kleen Wheels Disc and K&N Air Filters as the number one opinionate topic on the Forum.
This is my second season using the new gas and my nuts haven't fallen off(but they could if I could get a third set of teeth in exchange), the evaporator hasn't exploded and the compressor is quiter than before using the ester oil.
As was stated, go to Auto Zone or K-Mart and purchase the complete conversion kit plus the capacity low side pressure gauge and hose.
In addition to the normal conversion items I added the "Hot Shot" charge with 2 additional ounces of oil plus a stop leak and red dye to note where if you have a leak.
Happy Trails Beep Beep from The Spiderman in Houston!!!

I drive every car that we repair A/C on. Good job in a non airconditioned shop in N Central Florida. I do this to evaluate the cooling efficiency as a quality control issue and in a long running evaluation of how different models do with R-134a conversions.

I have a 4 lane divided road that I can drive 2 miles at 50mph. I place a digital thermometer in the center duct and turn on high blow and recirculate. The length of the drive allows the system to achieve a stable value or cycle if good enough. I grade systems by how many degrees off of ambient temp is achieved or by the length of the drive it takes to achieve cycling. In other words if the day is 96, I consider the A/C to be OK if it reaches 40 degrees off ambient or 56 degrees. (This will not cause cycling). If it was 80 out then the same car should hit 40 and probably would cycle first.

Most cars running in R-12 will cycle during this test even when its 96. That means probably a fifty degree drop. Some domestics have such good A/C that they hit low forties before I even get to the 2 mile stretch.

We have retrofitted hundreds of MBs and consistantly I see about a ten degree difference in performance. But there are abberations. I drove a 89 300e on the test last week. It was in for an intermitant lack of compressor (was the Klima relay). This car we had replaced the compressor and evaporator two years ago and converted (before I decided not to do any more pre 1990 124 bodies). To get to my 2 mile stretch I have to drive through a maze of back streets. This car was cycling at 44 degrees in high blow with the ambient temp at 96 and it did it in the stop and go section before the higher speed run. I have never seen an early 124 with such good air and it was 134.

I also drove a 300SE (the air should naturally do better on this car) this week that had been converted at a dealer (not locally). Even after pulling all the 134a out and evacuating and recharging; tuning the presssures for maximum efficiency I could only get 57 deg and it was a 92 degree day (only 35 degrees off ambient, no cycling in high blow). When I first tested it, it was doing 69, only 23 degrees off. The car probably still had a recirc door problem or an evaporator covered with leaves as often happens in the "Tree City". It was noted that the system didn't meet our minimum standard of 40 degrees off ambient.

Try it on yours and see what you get!

I got long winded on my opinion of 134a conversions so I though it best to state my factual opinions of other refrigerants in a separate post.

As stated hydrocarbon refrigerants are illegal IN THE US. Last I heard they were being used quite a bit in Canada: Beware! Other refrigerants are blends. There is no approved way to recycle blends!!!! It you put these in your system they will have to be vented to do any future work on the system (which is probably illegal, it is at least stupid). The other alternative is to have it disposed of as hazardous waste. I pursued this once and found that a ten pound cylinder would cost me 2-300 dollars to dispose of using the only local hauler that would even touch it. I'm sure the owner of the vehicle, that had the unknown quatity (found during standard refrigerant indentification, before hooking our recycler), released the stuff to the atmosphere as he was pretty upset when we wouldn't work on the car. He wasn't upset at us. He was upset at the shop in Georgia that did it to him.

5 Degrees lower
 

Brother of The Benz, stevebfl
You apologized for being so long winded.
All of us using R-134A would experience an additional 5 degrees of cooling if we would keep our hot air from being expelled and raising the interior temp of our Benz.
As our moderator you stand far above we who appreciate your wisdom and knowledge.
Happy Trails Beep Beep from The Coool Spiderman in Houston!!!

"All of us using R-134A would experience an additional 5 degrees of cooling if we would keep our hot air from being expelled and raising the interior temp of our Benz. "

Sometimes I have a real hard time with other than technical issues. I examined this sentence at least three times trying to figure out whether you were talking about the recirc door or heater control or something.

I think that I finally figured out the source of the hot air. Thanks for the laugh.

I have been using Envirosafe or "Freeze 12" for a year in my Saab with no problems. I'm now using it in the 1969 280 SEL and it seems to work just fine. It blows cold and I haven't been blown up yet or lost my nads. Life is good...
Thom

I'm running good old R-12. I keep an A/C thermometer in my center vents and typically at quitting time the interior of the car is 110-125 dF, ambient temp is 90+ dF. In less than 3 miles, in town traffic, I'm showing 40 dF at the center vent.

While the temp is 40 dF at the center vent, due to the high interior temp I don't "feel" cooling until I hit the open road. Once I get up to speed, the interior cools off quickly. Seems most of the heat is radiating from the dark brown MB Tex. By the time I get to the house the steering wheel is almost too cold to hold on to.

I'll stick with R-12.

Take Your Technical Cap Off!
 

Brother of The benz, stevebfl
Your right in asking if the recirculate door was open or closed; and I happy you found the joy in my remarks.
We all should be aware that 134A will not cool as well as 12.
In my old 1987 W124030 with 176,000 miles and with the exception of the manifold hose assy and one drier/reciever is still original and converted for the second season to R-134A.
Setting the temp control of the Automatic Climate Control A/C to 22 degrees C.(72 F) the cooling fan speed is reduced to maintain comfort on the hottest of days we have in Houston and frequently cycles the clutch off.
I don't know what the evaporator nozzle temperature drop is compared to the ambient temperature.
I do know that the return sample air satisfies the set temperature.
This brings to memory when Chryler Corp. converted The AirTemp Auto A/C units from R-22 to R-12.
The same complaints were voiced then yet we survived as we will overcome the not using R-12 in our older auto A/Cs today.
Happy Trails Beep Beep from The Spiderman in Houston!!!

Everyone please go back and read be459's post. There are R12 replacements THAT ARE EXPLOSIVE. This sounds harmless since it is used as refrigerant in a sealed system. But what if a compressor locks up making a spark?

I was told about these replacements explosive content several years ago and have avoided them. I also have posted warnings on mshop several different times.

Folks, it's not worth the risk. There has been debate here whether or not to convert an original R12 system to R134a and they are interesting. I have kept some on R12 and converted others. But that debate is completely benign as compared to whether or not to use R12 replacements.

Use R12 or R134a and leave the Freeze 12 and the other BOMBS for someone else.

be459's post is the first I've actually heard of an actual explosion, but I'm not surprised that it finally happened.

Is it really worth saving $50 or $100 by taking a risk of burning you or your family members?

Good luck,

There was a bit on 60 minutes (I think) a couple years ago where a fire department in the Midwest took junk cars filled them with hydrocarbon refrigerants created a leak and an ignition source and filmed it. Made an interesting display, sorta like a bit of the mideast in the midwest.

It's amazing it is still around in the US as it is definitely illegal to use in mobile A/C.

Whoa, Hold On Here...
 

What is it about Freeze 12 that you claim is explosive? The manufacturer specifically states that it is not flammable, and is approved for use as a direct replacement for R12. It's just 80% R134a & 20% R142b...

http://www.freeze12.com

[Edited by longston on 06-11-2001 at 05:17 PM]

Larry's probably thinking of OZ-12, which is/was a hydrocarbon (i.e propane/iso-butane mixture) which
replaces R-12.

Some of the blends appear to cool better even than R-12,
which should be interesting to those of us with old,
marginal a/c systems. Here's some websites at which to
fritter away your time:

The Autofrost site. This is the blend invented by George
Goble. George is mostly noted for "accelerating" his
BBQ grill by pouring a bucket of liquid oxygen over the
coals.

http://www.autofrost.com

The air conditioning alternative refrigerants message
board:

http://www.aircondition.com/wwwboard/alternative/

And last, but not least, the dreaded Cryo-Chem website!

http://www.cryochem.com/

Freeze-12 is not explosive. But when it starts burning, I think, poison gas comes out. It is a mixture of 80% R-134a (HFC) and 20% R142b (HCFC). The reason people use it because you can still use the mineral oil that R12 uses. R134a does not mix with mineral oil, so the lub job is done by R142b, 20% of the refrigerants. Do you really want to do this to your system, the oil is carried by 20% of the refrigerant thru out the system? The manufacturer said it is okay.

Befor you decide if freeze-12 is for you, here are my concerns:

1. R142b (HCFC) is the same family as R-22 which is used in the home air conditioning system. I read from some place that R-22 is very bad for the rubber seals, therefore, R-22 is not good for the car. If 20% of refrigerant is HCFC, how bad can it do to the seal. I do not know. The manufacturer says it is okay.

2. Freeze-12 needs to be liquid charged, if not, the percentage of mixture will be changed. In other words, if it leaks from your A/C system, in order to get the same ratio of mixture, you have to take all the remaining stuff out of the system and recharge it with fresh Freeze-12. There is a "problem". You cannot legally vent the stuff into the air. How are you going to service the system legally and cheaply? Maybe, the manufacturer has a recycler center to collect the remaining gas for a cheap price, assuming that you have the right equipments.

David

[Edited by be459 on 06-11-2001 at 05:41 PM]