[Greimann]

This was asked about in another thread and I though it deserved it's own topic, so as not to derail the other subject.



First know that hydrocarbon (HC) refrigerants like Envirosafe, Freeze 12 , Duracool, HyChill and the like ARE flammable. They are usually a mixture of propane and butane, with some other -ane's mixed in for good measure. Don't look at ad hype about autoignition temperature being higher than R134 because that is the temperature at which the products will ignite in the absence of a spark or flame. If you have flicked a bic, you know how sparks can ignite butane.



Doom and gloom out of the way, the bottom line is they work fantastic, especially as an R12 replacement. I put Envirosafe into my '91 Chevy truck and it absolutely works. My old R12 system blew a hose (so no evacuation hassles for me <img src="/forum/images/smilies/968/smile.gif" class="smilie" alt="" /> ) First converted to R134. I changed the hoses, compressor, receiver drier and orifice valve. The R134 just couldn't keep the truck cool. Especially after running for awhile. The cooling capacity just dropped off. I purged the R134, dropped in Envirosafe and the truck cools wonderfully. So well in fact, the evaporator sometimes ices up in moderately warm temperature. I even put it into my '94 968 that has R134 in the first place. Much better cooling, especially after running for along time where the R134 seemed to loose its chill power.



When converting an old R12 system you don't need to change the oil, vacuum down the system, or change hoses or seals (if they are in servicable condition in the first place) Hydrocarbon refrigerants have a larger molecule than R134 so they don't need barrier hoses like R134. They are also more tolerant of residual moisture or humidity in the lines, so vacuuming down is not necessary, and are compatible with the mineral oil used in R12 systems.



What you do need to do is change the fittings to the R134 style and it would also be a good idea to change the receiver drier. That device is a dessicating filter that gets used up over time.



Some AC shops may not touch the stuff because there are some EPA regulations regarding their use. They ARE considered a drop in replacement R134, meaning that is perfectly legal to do that. They are NOT considered a drop in replacement for R12. Also the EPA covers the loophole of what they consider a "sham" retrofit of R12 systems. In otherwords, you can legally drop in an HC refrigerant into a system that was converted from R12 to R134, but you can't do the HC conversion back to back with the R12 to R134 conversion. Seems silly but that is the way it reads. So an AC shop may shy away from this altogether. You can always ask the dude and see if he will do it.



If you are a DIY'er, this is a moot point. There are no regulatory bodies looking over your shoulder. I say try it. You just need the R134 conversion fittings, a can tap and pressure gauge setup. The other good thing about HC refrigerants is that you only need 1/3 as much for R12 system and .38 as much for the R134 systems. The compressor doesn't work as hard either!



I encourage you to research and learn about hydrocarbon refrigerants. Lots of googling on those terms turns up a lot.



I got my stuff from here (the 6 pack of the regular stuff for $38): http://autorefrigerants.com/co00033.htm

And be sure to read their tech sheet: http://autorefrigerants.com/Envirotechnical.htm

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[968 Cab]

perfect timing! Thanks! The R12 in the 968 Cab was "drained" by the dealer and now I have to convert or replace (I actually have a 25lb can of R12 freon, but cannot get anyone licensed to fill the 968!)



This is a good option, so thanks in advance! just placed an order!



Interesting to note that "No flushing or oil changes are required. The only difference is that ENVIRO-SAFE is installed as a liquid." not pulling a vacumn is the recommended fill method.



I'm going to replace the receiver / dryer though beforehand. Already had a leak check done and the HVAC guy confirmed the system is not leaking, there is mineral oil in the system, but obviously no R12 in there anymore. Anyone spot any issues of introduding the HC into the system if there are traces of R12 remaining?

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[968 Cab]

I called Enviro-Safe (Michigan) 1-800-524-5987 and thought this info would be useful.



1. 12aHC is completely compatible with old R12 freon – they can mix, so no need to remove any residual traces of R12 in an older system before adding HC



2. For new install, there is no need to pull a vacuum before you fill the system with 12aHC in a liquid state – just have to have the oil in the system



3. Enviro-safe Oil 3 – is 4oz of ester oil in pressurized can that is compatible with MINERAL oil in the old R12 system.



They were VERY helpful on the phone! I'll post a follow up after the R&R on the 2 Porsches where I plan to use HC.



I decided to get the Quick-kit with R12 tap/chargehose and Dyecharge/Refrig. combo (instead of 134a tap/chargehose and conversion fittings): $39.95 ($4.00 shipping)." so that I did not have to swap fittings since the LP fill valve is so close to the hood. I'll be installing a new compressor and dryer in a 85.5 944NA before filling with HC and then filling the 92 968Cab with HC as there are no leaks in that system (local AC shop did a leak test with nitrogen for me recently - gratis!). I'll post the results including temps at the vent after the installation/refill.

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[dlearl476]

Thanks for this thread guys. It was 121 degrees by the dash thermometer today and I'm crying uncle. I'm going to check into the compatibility for the 968 and the 911, which just had a new rotary compressor and dryer installed. Neither car has AC that compares to a GM vehicle, and I don't expect them too, especially the SC, but come on. I need some HELP! <img src="/forum/images/smilies/968/ohmy.gif" class="smilie" alt="" />

Hopefully something will be better than what I've got there now. I really didn't pay attention to the AC job on the SC, but I have a feeling they put the new stuff in.

btw, I'm assuming my OEM '92 is still R-12, yeah?

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[968 Cab]

Yep - 92 Porsche 968 is R12 Freon - the banned stuff.... and if you are in USA or Canada, it is illegal for any certified shop to fill R12 into a car now (don't bother to ask, even if you have a huge can of the stuff) - so the 911SC probably got a R134 conversion and fill.



My HC kit should be here in a few days - it just shipped. I noticed that there are lots of eBay kits available too - for less $$ if you know what you are looking for.

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[dlearl476]

Thanks, I think I'll talk to my mechanic tomorrow and wait for your post, then go from there. It's something I've shied away from in the past, but I'm on a new program of buying tools for myself instead of for my mechanic, I'm anxious to hear your results.

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[Greimann]

Also on the subject of improved cooling, it is also a good idea to clean the condenser core once in a while too. That is the radiator looking thing in front of your engine radiator.



Over time, the fins get loaded up with dirt, gravel, bird feather, insects, etc. Spray some degreaser all over it and rinse with a good high pressure stream of water. Work carefully , get every single fin clean and you can improve the AC effectiveness by a good margin if the thing is really dirty.

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[dlearl476]

Update from my mechanic. It is not illegal to fill and R-12 system with R-12, at least here in Nevada. What IS illegal in manufacturing R-12. They have plenty of R-12 which is what is in both the 968 and 911.

The bad news is that the 911 isn't gonna get any better than it is. The good news is that MAYBE the 968 just needs a re-charge. I'll find out next Tuesday (right after the heat wave breaks! <img src="/forum/images/smilies/968/dry.gif" class="smilie" alt="" /> )

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[968 Cab]

Here are the results of the HC charge and a few tips



1. Get a spray bottle (old windex etc) and make a soapy water solution like you would use to blow bubbles. You will use this as a leak detector by spraying a little on each coupling after you fill the first bottle of R12a. It works really well to find leaks. Get your 19 and 22mm open end wrenches ready too. In fact, it might be a good idea to go around all the AC lines and just snug the fittings up a little before you start charging the system.



2. The LOW PRESSURE valve is mounted on the compressor on the 968 – you charge the system from this location, so you need to raise the front of the car on jackstands and remove some of the shrouds to gain good access. I just removed the front batwing under the nose.

a. Clean the area around the valve – I used a shot of brake cleaner and let it all dry before starting the charge



3. I called Enviro Safe and they said there is no need to pull a vacuum at all in using the HC based EnviroSafe R12a coolant. The HC coolant is compatible with old R12 and R134a and mineral or ester oil, so there is no need to pull all the old oil and coolant out. Just make sure there is oil in the system.



4. The 968 takes 3.3 oz of oil and 313 gms or 11.1 oz of R12a – the charge bottles come in 6oz refrigerant and 5 oz refrigerant with dye which makes for almost the perfect amount.

a. Good idea to use the 5oz can with Dye to co a quick leak check

b. Detaching the charge hose results in a little of the gas escaping, so 2 x 6oz would probably be OK



5. If you need to add oil to the system (if it was completely emptied by a vacuum pull before like mine was) add this first to the LOW PRESSURE (under the car on the compressor fitting).



6. With engine off, and NO vacuum, attach the can with the dye first to the LOW PRESSURE and then proceed to fill until the can is empty. Only takes about 20 seconds to empty the pressurized can. I used a triple beam chemist balance to weigh the before and after to get an idea of the contents in the can – the weight indicated on the can is very accurate.



7. before you add another bottle – and with the engine still off – take the soapy water spray and go over each AC line connection in the engine bay again. Pay special attention to the line connections at the Receiver Drier and the 19 & 22 mm connections to the Condenser (the smaller black radiator right at the front behind the grill). I had a small leak there from a loose fitting – sealed up nicely with a turn with a 19mm. If you have any bubbles, or hear hissing sounds – STOP adding anything more. There is a leak in the system that must be repaired before you can recharge the system any further. Most common problem is a bad AC line (cracks, etc.) or bad “O” rings somewhere. I bought a AC “O” ring kit off eBay for $15 / 270 pcs and I wish I had this before I swapped a compressor on my son’s 944 last week. Just 8 Porsche “O” rings cost me $10 and I still had to go out to source a few more during that retrofit! So it’s handy to have a few extra sizes around before you start.



8. If there are no leaks, then with the first can in the car, get the 2nd can ready to fill the system and proceed to fill. Make sure you are connected to the LOW PRESSURE (under the car on the compressor fitting). The high pressure side can reach up to 150psi which is definitely NOT the place you want to connect to with a thin metal can full liquefied gas.



9. When you are sure everything is connected right, start up the car (careful as it will be up on jackstands still), then turn the FAN to MAX, the temp dial to COLD and hit the AC switch – you should hear the compressor kick in, the idle speed drop a little and with the R12a can held upside down, crack open the valve and the contents should be “sucked” into the system by the Low Pressure side. The engine should be running all the time during this process. Adjust the AC controls in the car so that you get a blast out of the centre dash vents.



10. Back in the car, the temperature should start to drop noticeably and if you have a thermometer in the center vents, the temps should drop below 40F and maybe even lower depending on the outside temps and humidity. After about 60 seconds, the AC should be pumping ice cold air and operating as it came from the factory. Take a look into the little round window in the “sight glass” and you should see a “river” of activity with the AC on – a stream of clear liquid (the oil and coolant) or maybe just a little foamy solution. With the AC off, it should just be clear.



11. In the 968, I started to get cold air even with the first 5 oz bottle of Enviro-Safe R12a – and after adding the 6oz bottle, it was very cold again. I’ll post some temp readings out of the dash vents when I get hold of a thermometer. But it works again and it blows COLD.



12. Pretty easy to do, only $40 or so from eBay (better kit than from the mfg actually – more R12a, better hose with gauge, thermometer and leak detect LED light included).



CAVEATS – make sure you connect to the LOW PRESSURE fitting. The can could possibly explode if connected to the high pressure side next to the receiver dryer and that could lead to serious injury.



Only do this if you are comfortable handling the AC gases – there will be a little escape of fumes when you disconnect the charge hose each time and even change the bottles of gas – you will get a little nauseous – the R12a does contain propane and other gases so be careful. I would certainly NOT do this in a closed garage. I opened all the windows, the garage doors, and still got a little sick from the fumes.



Tidy everything up, lower the car, and drive off in cool comfort!



Here’s a supplier on eBay with a good price on the kits. I’m going to get another one as it is pretty cheap to have around during the summer and this kit comes with all the right stuff you need. http://cgi.ebay.com/ebaymotors/ws/eBayISAP...sspagename=WDVW

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[Greimann]

Great writeup!



Another added benefit is that since you are only charging about 1/3 the volume of a conventional refrigerant, the compressor doesn't have to work as hard. This will add to the longevity of the compressor and you also don't feel the engine bog as much when the compressor kicks in - less parasitic power loss!

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[flash]

question - my jeep has a perfectly functional system - the dealership says it's kicking out 52 degrees and they say this is normal - i'd like to see if i can get it a bit colder (the jeep is black) - will the envirosafe output colder than 134?



dave, i seem to remember you saying it was a bit colder - yes?

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[Greimann]

Its is colder than the system in the 968 and stays cold in high ambient temps. I remember running on the freeway through 104 ambient and only needed #2 fan speed to say comfortable. At least my car seemed to loose cooling capacity on the R134 after running for a while. I have a suspicion that I have a hardware issue, perhaps the expansion valve. At idle the cooling drops off dramatically, but at 1500 rpm and above - Chilly Willy.



For my converted '91 Chevy truck. The Envirosafe transformed the truck to a refrigideezer. No complaints. The only technological complication in the truck is that in mild temps (70 to 75), the evaporator freezes up. You have to switch off the AC for a couple of minutes to let it thaw. No worries because you still get cold air while it thaws. Higher ambient this is not an issue. This is because the lower operating pressure of the envirosafe does not kick off the pressure switch, which is calibrated for R12 (in the truck).



Bottom line is, this stuff is the most efficient refrigerant available. It should make your Jeep much colder.



R134 operates at such a high pressure, high ambient temps reduce the efficiency of the compression - expansion refrigeration cycle. The relatively relaxed operating pressure of a hydrocarbon refrigerant gives a wide operating range of the system.

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[968 Cab]

Dave -thanks for putting us all on to the HC option - it was really easy to do actually and although I have to get my dad's thermometer to check the actual temps, when I put my hand up to the dash centre vents at max fan / coldest setting, it actually got so cold after 10 seconds that it was uncomfortable! Both the 944 NA and 968 I charged up today were really cold. Colder than my 951S where I recharged the R12 system last year.



The only strange thing that happened is when I fully charged both systems, and went out for a test drive, the compressor on both cars started making some not so friendly mechanical noises for a few minutes. On the 944NA, I thought the new rebuilt compressor had a bad clutch, so we cycled that on and off a few times and every time it engaged, we heard some pretty alarming mechanical sounds - almost like a bad bearing. But it went away pretty quickly and now it is quiet. Strangely, the 968 did the same thing! I suspect that the clutch / bearing was the culprit in both, but since they are both quiet now, I'm not going to pull the compressor to check.



I'll try to get temp readings from the car and post later.



I just bought more of the R12a and oil charge on eBay - $40 kit provides a LOT more than from the mail order supplier. check out eBay listings for R12a such as this one http://cgi.ebay.com/ebaymotors/ws/eBayISAP...item=4562998318



All the tools you need are there, plus there is a little more R12a provided for the same $$

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[Greimann]

[quote name='968 Cab' date='Jul 23 2005, 09:25 PM']The only strange thing that happened is when I fully charged both systems, and went out for a test drive, the compressor on both cars started making some not so friendly mechanical noises for a few minutes. 

[right][post="7815"]<{POST_SNAPBACK}>[/post][/right][/quote]

Interesting, I didn't have that issue with my compressors. I can only speculate that it may be cavitation sounds inside the pump. Since there is less volume of fluid, untill it gets distributed evenly, the pump may starve occaisonally.

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[968 Cab]

[quote name='Greimann' date='Jul 24 2005, 08:49 AM']Interesting, I didn't have that issue with my compressors. I can only speculate that it may be cavitation sounds inside the pump. Since there is less volume of fluid, untill it gets distributed evenly, the pump may starve occaisonally.

[right][post="7818"]<{POST_SNAPBACK}>[/post][/right][/quote]



ahh, that makes sense actually. I was a little concerned that the rebuilt compressor we installed in the 944NA was a DOA, but it pumped cold air almost immediately. We shut down the first time it started making noises, and only restarted when I checked out the AC clutch. The system gradually quieted down within 90 seconds and it soon went quiet. Then when a similar - but different noise emerged from the 968 on start up, I suspected something when starting up from basically 2 dry systems. I made sure there was enough oil in both systems before filling.



Weird thing is that when we started up the car to fill the 2nd cannister - in both cars, the compressor remained quiet during the initial fills. It only developed the mechanical noises when we closed everything up and went on a road test - maybe a little higher RPM's. I'll keep an eye on things - hopefully it was only a little cavitation and priming as you noted.

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[flash]

well, sounds like a no brainer for me - i'll order the stuff this week - the long hot trip to denver will certainly be more enjoyable if it's cooler



thatnks for all the work

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[Steve]

It is wonderful having a roadster with air conditioning. It is the best of both woulds with the 968.

I just put in two cans of R12a and WOW! What a great cold blast! My system is right at 45 psi with the two cans . I got my Kit with a instructional DVD from ronieboy44 on Ebay. I wish I would have known how darn easy this was to do a long time ago!

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[wiseman]

Well I did a lot of reading on this post about the merits of using R12A from Enviro-Safe. With the 98 degree heat here in Florida, I need to recharge the 92 968 which should have R12 in it. Had it done last year for $20 and its not blowing cold again. This R12A or now called ES12A (Enviro-Safe) sure is cheap enough , the whole kit is only $35 and it can be dumped in to R12 or R134A with no issues and no purges. So unless anyone says something bad here, I'll order the kit next week.
My second question is that when I have the air blowing, I can't get it to stop blowing out of the defroster vents also. I, ve looked at everything I can while I had the dash out.............but I just don't know what shuts the defrost off when you want the air to come out of the vents. I've moved the sliders back and forth, and nothing happens. Need some advice guys.

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[Monstrous4Banger]

LOL Envirosafe? Did another patent run out?

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[banditsc]

Been using the ES12A Envirosafe stuff for a while in a few cars and it's been working great for me.

For the defrost the slider on the center vent should shut a flap in there to cut off the defrost vents.

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