1986 Porsche 911 AC Issues

[Jay McGrath]

had a schrader valve leak and slowly lost R12 to the point the AC was barely cooling. I fixed the leakage problem and at this time was at the point I was not going to put R12 back in for several reasons: cost, environmental and ease of obtaining it today. I have read a lot about a R12 replacement using hydrocarbon refrigerant called Enviro-Safe which cost about $5/can. I won't debate the pros and cons about using this refrigerant, only that it works. I called Enviro-Safe and spoke to their technical personnel and I liked the fact that you only had to use 1/3rd of amount of Enviro-Safe compared to R12 (13 oz vice 39 oz).

With R12 I was barely getting a 25 degree delta T (temperature) between ambient and the center dash temperature. With Enviro-Safe installed which is colder and more efficient that R12 I am getting 38 degree delta T 88 degree ambient (80% humidity) and 50 degree center dash temperature.

My compressor pressures with Enviro-Safe are Low - 40 PSIG and High - 240 PSIG with R12 pressures were 35 PSIG and 225 PSIG. I don't have any history as to what the original AC performance was when the car was newer, but I am told I am lucky to have what I have. I spoke to my local Porsche Independant repair shop, and he told me that they normally shot for 25 degree delta T as sufficient for these older Porsches.

My question, is is 30 to 38 degrees delta T fine with these cars or should I shot for approximately 30 degrees center dash temperature vice the 48 degrees I am getting now?

[darrin]

Not responsive (though I believe folks that successfully rebuild their ac using the griffins/etc. solutions generally see vent temps in the mid-30s), but question on Enviro-safe -- are they still using a propane-benzine mix as a substitute for (inert) freon?

[patkeefe]

Be glad you are getting cold air to cool the cabin. You say you are getting 48F split return to supply now, even though 88-50 = 38F. You are assuming you have 88F return air, or is 88F the outside ambient? How much air are you mixing with the return air now? Suppose you want to go to 30F split...how do you propose to do that?

And, buy a fire extinguisher.

[Jay McGrath]

The temperature ambient outside is 88F and 80% humidity (Florida) and my cabin center duct temperature is 50F. I won't argue the issues of Enviro-Safe (yes it is flammable, but so is gasoline.)

[Jack Stands]

I know folks have used similar products (Duracell) in old GMC Motorhome successfully, though it’s use is not DOT approved. I worry about having the system serviced as it shouldn’t be recycled with R12 or Rz134a. All refrigerants are ultimately flammable, but this mix is more so.

[Koizumi]

Enviro-Safe is no more or less flammable than R-12 or R-134a. And it operates with way less pressure than either dinosaur refrigerants.

One should have an extinguisher in every old Porsche regardless of whether or not the end user has Enviro-Safe in their system... For a cornucopia of obvious reasons!

———> Quick question, how much did you use to fill your system?

[Jay McGrath]

Based on the fact my 1986 Porsche 911 engine label states 39 oz of R12, I simply divided by 3 and the result is 13 oz of Enviro-Safe. I initially evacuated the system to check for leaks and then added the first can, started the car and put the AC on maximum then stated the car and added the second can (each can is 6 oz). I did not add the additional oz as it is too hard to add one oz with a six oz can. Just as an update, at 2000 RPM the temperatures have dropped to 38 degrees F. I have never had it this cold. I am sort of sold on this stuff as a replacement for R12, it works. Additionally, I had the car serviced and charged with R12 (very expensive) and never got this cold. I think the best I ever got with R12 may have been in the low 50's.

[Koizumi]

Thanks for the info.

I, too, have been using the two 6oz can amount (12oz total) for my ‘84.

My results mirror yours.

Noteworthy observation: their upgraded “Industrial Grade” variation of Enviro-Safe gets even colder than the standard version. And it costs the same

Cheers

[Bigtoe32067]

Just for the record r12 and r134 is not flammable in any way shape or form and a few years ago enviro safe was fined for selling flammable refrigerant. Don't know about the new stuff.
I did AC work for 25 years and when r12 starting phasing out there were many new companies selling replacement refrigerant and most of them were highly flammable and people found out the hard way.
It got to where we tested each new refrigerant before we'd try it.
Tony

[Bigtoe32067]

Also fyi you can still buy real DuPont R12 on eBay for about $30 a can. A long way from the .79 per can we used to pay.

[kuehl]

1. My question, is is 30 to 38 degrees delta T fine with these cars or should I shot for approximately 30 degrees center dash temperature vice the 48 degrees I am getting now?
Usually, when we think of "delta" it is how Pat expressed it, the evaporator or air handler air inlet temp vs the vent temp. If you are saying you have a 88F humid ambient (outside car temp) with 50F at the vent, that is a small improvement over what you would see with R12 when the system is properly charged. R12 systems would run in 50 to 55F vent range.

2) at 2000 RPM the temperatures have dropped to 38 degrees F .
Yes, vent temps drop because you are increasing the airflow over the deck lid condenser and increasing the refrigerant movement (compressor speed). And, if the car was heat soaked the vent temps will drop as the system continues to remove moisture and heat from the vehicle (it's a recirculating system).

So, to answer your underlying question, are you doing better with Enviro-Safe's product? Yes. However, you could use R12 legally or even R11 or R22 illegally.

BUT, since many DIY's read these posts and some are not looking at the bigger picture, I will recite some of the comments made in this thread by experienced vehicle owners.
1) Using any refrigerant that is not "approved" on the EPA's SNAP LIST
or
2) Knowingly using any refrigerant which presents a hazard to other occupants in the vehicle, service personnel (mechanics), or fire & rescue personnel, is simply unintelligible. Example 1: you are not allowed to have a propane barbeque grill on your condo's deck in a 'multi-dwelling building, however you feel you are a safe master chef. One day the condo next door to yours catches on fire (for whatever reason). Rescue personnel can't see your propane grill on your deck. And you are not home to tell them about it. You cannot fathom what happens when you get home. Example 2: you should have 5 lugs torqued to 100 lbs pounds on your left-hand front tire. You're missing the 2. You drive the car to the alignment shop cause it is "just down the street" and along the way the stress cracks what you got going around the corner and you slide across the street into my SUV filled with my kids. Do you think I'm going to wait for the court system to serve justice?
Now, the odds of your car going up in flames my be small, however the cost to you when your insurance company finds out, or the future car owner finds out, or the future mechanic finds out? Maybe you want to have a get-away bag stashed somewhere with lots of bitcoin, extra fake passports, a list of private airports in your wallet.

[Jay McGrath]

I would like to thank all those that answered, but there are a few misnomers stated: R134 can be flammable when in the presence of an ignition source while under pressure not to mention the noxious fumes it produces see Chemours Corp page 20 report on R134). R12 produces phosgene gas under an ignition source which is deadly. So, I guess the moral of the story is pick your poison. It is NOT illegal to use Enviro-Safe in my car, I don't know where that is coming from as it was mentioned above. It is true that Enviro-Safe was fined $300k, but not for selling Enviro-Safe R134a, it was fined for its R22 replacement. Lastly, I ended up installing the Griffith's Kuehl evaporator kit which I got from Pelican and now getting 38 degrees F out of my dash vent at 2000 RPM. The original evaporator just was not as efficient as the new one, but with both Enviro-Safe and the new evaporator I am getting nice cold air in Florida. The directions that came with the kit were great, the only issue I had was the ease of which the aluminum fitting for the evaporator control valve galled compared the original fitting was brass. Brass is much stronger than the aluminum fitting and did not gall when the metal fitting from the hose was attached. I had to run a die over the fitting to restore the threads. Other than that, all is great. Thank you all again.

[kuehl]

Jay. Good to hear you are back on the road again.

Enviro-Safe’s MSDS stipulates the composition of their R134a replacement is 99% Petroleum gases, liquified (CAS No 68476-85-7). In 2015 the DOJ (aka Depart of Justice; Uncle Sam) noted Enviro-Safe agreed to pay a civil penalty and “would cease marketing and sale of unapproved flammable hydrocarbon refrigerants as substitutes for ozone depleting substances (ODS).” And the DOJ further stated the “EPA has not approved any flammable hydrocarbon as a replacement for ODS in systems not specifically designed for flammable refrigerants and has warned that use of flammable refrigerants in those systems presents a risk of fire or explosion.” At that time, the DOJ was addressing Enviro-Safe’s ES 22a and ES 502a products.

The EPA (US Environmental Protection Agency) updates the list (the SNAP list; Significant New Alternatives Policy program) of approved and not approved refrigerants for various use sectors, for example automotive (aka MVAC; Mobile Vehicle Air Conditioning). Under the classification of “not approved” the EPA’s Snap List clearly states “All flammable refrigerants" and goes on cite a few brands. Just because a specific brand or trademark is not on the list does not mean it is approved. The EPA's SNAP list if ever-changing. The wording “all flammable refrigerants” means “ALL” flammable refrigerants. I could imagine if wanted to play with words you could have a scholarly debate on what specific brand or trademark of flammable refrigerants is or is not on the approved or not approved SNAP lists. And, you could have fun playing hopscotch with what specific authority at the federal level or state level has the final word as to whether a 99% flammable gas is allowed to be used in a mobile vehicle, however, I sense it would be a rather expensive game to play. If flammable refrigerants were the "best thing since pop tops of beer cans" I would imagine every automotive repair shop that services vehicle AC systems would have cases of flammable refrigerant stacked up and there would be signs and banners in their windows shouting it out.

Sorry to hear you buggered up or galled the aluminum MIO (male insert o-ring) fitting which the evaporator outlet hose connects to. It would be difficult to successfully bond a brass or steel fitting to the aluminum tube and have it last for long; most of the 86-89 year OEM evaporators have a brass/copper manifold bonded to the aluminum core tubes and they all leak sooner or later). I, myself have ‘galled’ the fitting at one time when I was not careful to align the hose fitting square with the MIO nut; I was in a rush. Although our instructions do say “Hand tighten the nut as much as possible, and then use a wrench to tighten the fitting” I have underlined that statement in the instructions for future shipments, and I have added an additional note stating “fully insert the hose fittings tube into the evaporator outlet pipe to ensure the threads properly align”.

[Steve Marshall]

Is Enviro safe still working good for you? I've got an 86 with the 39oz sticker on the heater blower duct. That's the only place I've seen that quantity of freon. All other year Carreras have a 47.6 oz sticker and the AC systems were the same as 86. Could they have anticipated the move to R134 and stickered the 86's incorrectly and fixed the issue for 87 - 89?

47 oz of R12 is in the Bentley Service Manual.

47.6 oz R12 is in the owners manual.

43 oz of R134 is Porsche Service Bulletin on Retrofitting R12 to R134

Conversion formulas you find on the Google are all over the place. The one that seems the most thought out is 90% of R12 minus 4 ounce. This works out to 39 oz of R134.