Porsche 911 Air Conditioning Revival. Going from R12 to R134a
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- Опубликовано: 11 май 2023
- Like a lot of Porsche cars out there, this 911 Carrera had the air conditioning taken off at some time in its life. When the air last ran, it was on R12 refrigerant, which is banned since 1994.
To get this air conditioning working again, all the hoses, evaporator, and compressor were changed out for new parts.
The molecules of R134a are smaller than R12 and could leak out through the hoses and flare fittings that R12 systems used. Also, R134a systems operate at higher discharge-side pressures than R12, which can cause compressor seals to leak. You need to run less R134a than R12.
I got this formula from Techtown.com. (Kurt tells me this is still too much gas and to use the pressure reading on the air conditioning machine)
Formula: (R12 Charge Specification x 0.9) - 0.25 lbs. = R134a Charge Level
As an example, let's say the R12 charge specification is listed at 2 lbs. You would do the following:
Example: (2 lbs. x 0.9) - 0.25 lbs. = 1.55 lbs. 
Авто/Мото
Looking forward to another great lesson.👍
Thanks
Kurt
Excellent, as per usual!
Thanks Chuck
Excellent video Kurt, and perfect timing, as the a/c in my '78 SC has gone kaput. In the fall when I bring in my car for the top-end, I'll most likely have you do the same to my a/c system.
Sounds good.
Kurt
Thanks for the great video! The previous owner removed the AC from my 1980 SC but included all the old parts. I will probably go do a hose company to see if the can make new hoses using the old ones as templates. It's not fun driving in Atlanta without AC.
You can just buy the hoses on the open market for that car. I would also go to a new rotary compressor if the car has already been updated. The piston powered York compressors are pretty porous and inefficient.
Kurt
Great video Kurt
Thanks
Kurt
Thanks Kurt for the great video and tutorial! I learned quite a bit. There’s always a bunch of tips and tricks that make the job much easier, thanks for all the knowledge! 👍 I have the originals and replacing the lines is on my list, but all I have is Jack stands, and a small garage, but it’s doable!🥲 It’s almost a must with R-134 (which I converted mine to) I’ve read it’s a smaller molecule from R-12, and the new hoses have a barrier liner in them. My shaft seal failed and I tried replacing it twice but couldn’t get it right, so I ended up purchasing a new compressor, which I thought was pretty reasonable. They’re great compressor’s. I can’t wait to see what the problem is with the Turbo (WUR is my guess, seems likes those things are always going out) I know your channel will keep growing! Thanks again! Cheers Darren! Ps: Oil change, and valve cover gasket replacement went great, the rockers were tight and and dry, the cams looked great! 🤓
Dernie,
I have done the job on jack stands before, its not fun but it works. Changing the shaft seal rarely works in my opinion, especially on a 35 year old part. Usually when the seal fails it is due to not only seal where but complete compressor wear. So when you put a new seal into a old worn compressor the odds for success are pretty low. The same thing is happening with warm up regulators. These days I am finding that even after a rebuild the parts are not always functioning correctly. One of the biggest problems we are finding with WUR's is the bimetallic gets weak and cools off way to fast. This ends up resulting in overly rich condition on a Warm re-start and surging.
Glad to hear your oil change and cover re-seal went well.
Kurt
@@klassikats Thanks Kurt, do you have a preference on hose replacement companies? Can you make the bimetallic strips? That might be a nice business rebuilding WUR with a new strip for the correct function out of the box. Being able to test one must take some specific knowledge. I replaced my reference sensors and then had and intermittent no start problem, it turned out one of the sensors went bad, it happens. I look forward to your next video. Thanks Darren!
Dernie,
So I usually do a combination of making my own hoses and buying some when time is short. The issue is where I buy from, they won't sell to the general public, and I don't usually buy from retail suppliers. You could try going to griffiths.com/. He makes a lot of hoses although I have found some clocking issues and hose length issues when using his stuff.
For WUR, I can't make a bimetallic spring. You would have to have so much information on pressure and the spring's rate of change and there would have to be so many different types for the different spring rates that I could not see it as a viable business idea.
Kurt
Perfect video. My next project on the 3.2
Good timing.
@@klassikats right! Especially after going for a drive this morning and I had to lean forward to vent my t shirt which was stuck to my back. 😂
You can also charge with Butane gas without modifying anything.
In fact, the new gas, R600A, is mainly made from it, and is just as flammable. So 1 kg of gas in the car is no more dangerous than the 85 litres of fuel in the front tank of the 911 !
The manufacturers don't tell us because it doesn't make enough money for them...🙄
So its true that butane can work in an A/C system although there is no way that I would put it into an automotive A/C system. R600A is also not an automotive rated gas. it is used in refrigeration units and not in mobile A/C units. There are currently three types of A/C gases used in automotive applications, R12, R134A, and 1234Y. All of these gases are mildly flammable under the right conditions. However, no where near the flammability of butane.
Kurt
@@klassikats And the flammability of 85 litres of premium petrol is higher than that of less than a kg of butane !
Good evening Sir,
I just want to congratulate you and say THANK YOU so much for taking the time to do this video and sharing your knowledge & experience, it helps a lot !!!
I just got new hoses for my 1978 SC, I just took them all out and I am in the process of putting the new ones in, I live in San Antonio, TX, it is HOT here !!!
I plan to finish this up over the weekend.
Last year, I recharged the system, it had a leak, after doing some troubleshooting, the technician found some black residue, he flushed the system, recharged it and it worked fine, however, one hose was totally leaking, so decided to change all hoses.
I will flush both condensers before I connect the hoses.
I have some questions, I hope you can shed some light for me:
I got a new dryer and expansion valve last year, should I replace them ?
Should I be worried about the black residue found last year, even though the system was flushed ?
Thanks in advance.
I would install the new drier bottle, but it sounds like the expansion valve is working and I would not change it. The black residue is most likely coming from the compressor and depending on its wear you will most likely still see some in the system. Flush it out and continue on.
Kurt
@@klassikats Thank You Kurt !!!
Thanks for the video. Would recommend a shop in the metropolitan Boston area that does that job well? TIA
Sorry I dont know any shops in the Boston area.
Kurt
Great video! What is the Denso model you used as a replacement?
it was a 471-0124 model.
Kurt
@@klassikats Thanks Kurt! Will this model work for an '83SC as well?
@@garmentmkr The 83SC bracket is different. You need a Sanden compressor to fit if you have an existing bracket.
Well done, I like that gas leak detection, do they make one for carbon monoxide that you can recommend? On my convertible (Alfa Romeo Spider) with the top up I get gas coming in that I can't smell but when I get out of the car my head is spinning so I only drive it with the top down.
So there are a bunch of different gas analyzers on amazon, you might be able to find one that fits your needs. Also check your exhaust system and make sure there are no leaks forward of the cabin, that is usually what will make you sleepy or nausea while driving.
Kurt
@@klassikats Hi Kurt, you are correct my exhaust is leaking at every join and a tiny spot on the manifold. Hi had a professional muffler shop look for leaks when I went to have the tail pipe end bent down would like the original muffler. This was done a few years ago, I tried to call him last week only to find out that he is no longer in business. I think I will buy some RTV for exhaust system and do it myself.
Thanks.
This is applicable to many old cars ,however this condenser looks warped ,you can see its bent a bit due to excessive heat but it can still work anyway..A new one would have been better.
The rear condenser is bent to fit the shape of the rear hood and not from heat. A new one would look exactly the same.
Kurt
@@klassikats ok so the condenser is behind instead of being in front so this would suffer from air to heat exchange because from the rear you cant get air flor through it effectively and this can affect the cooling.I wish it was placed in front rather and you have very long long hose fron there to the back but its similar for the vw bus T3 airconditioning.
So the air flow comes from the engine pulling in air for combustion. There is also a second condenser up front under the car that gets road speed air flow as well it has its own electric fan blowing air over it.
Kurt
Hi Kurt,
Thanks for the very insightful video. I was browsing through your videos looking for info related to heat exchangers but was unable to find one. I am restoring a 1978SC and since weather is usually nice where the car lives (Mexico) I deleted the heating system. Some forums have suggested that you should never leave the heat exchangers on the car if they will not be connected to the engine hoses (which I deleted). I could of course put a set of headers but that would entail dropping the original silencer as well, which I don’t want to do. What’s your tale on this? Would it be feasible/appropriate to simply cut the heat exchangers’ sheet metal to leave the internal manifold installed as headers? Thank you in advance for your comments. Best regards from Mexico.
The heat exchangers are an important part of the engines cooling system and should never be taken out of the system. If the hoses are disconnected and plugged it will cause the engine fan to over cool the cylinders resulting in eventual damage to the engine. If the hoses are not plugged it will result in the engine being under-cooled resulting in eventual damage. There is no gain in removing the heat exchangers and if you do not want heat just dont turn on the heater.
Kurt
@@klassikats Thanks Kurt. An unexpected yet insightful answer to my question!! Thank you for taking the time, your comments are always super helpful. Cheers! -Mario
Hello Kurt thanks for the video. My 1985 911 needs this service. I live in San Diego. Can you recommend a shop?
Sorry I dont have any shop contacts in that area.
Kurt
I’ve got to find a decent shop to do this conversion on my ‘80. My normal mechanic who has been working on the car estimated that it would cost like $6400 for the conversion. Seems ludicrous
Yes that does seem high. where are you located?
Kurt
Sources from proper barrier hose???
If you want to make your own hoses A/C barrier hose is available pretty much every where from NAPA to Amazon. If you want to buy pre-made hoses to suit your Porsche I would check all of the regular suppliers like Partsklassik, Pelican, or ECS tuning.
Kurt
Congratulations, you lost 15 HP! I took it all out of my 84 Targa. When I get too hot I put the top in the trunk.
But at least he is comfortable in the 118 Degree heat in Arizona. I would rather loose the 15HP than be sweating my ass off sitting in traffic.
Kurt
in118 degree heat and jn traffic, the porsche engine will overheat and he will have to turn the AC anyway.@@klassikats
Obviously your engine needs some work. I would be happy to resolve your overheating issues so that you can be comfortable in your car at 118° outside with the A/C running.
Thanks for watching
Kurt
Kurt,
Just purchased my 84’ 911 and the A/C isn’t working. I’m 4hrs from flagstaff AZ wouldn’t mind taking a morning ride and return with working A/C. What would be the cost for this?
It takes about a day and a half for this kind of job. Feel free to email us at contact@klassikats.com and we can set up a time to talk.
Kurt
Cant you use or wont you be better off with aluminium lines instead of these hoses and use the hoses towards the end of the pipes.
Aluminum pipes would not work in this application. Firstly nothing is available in aluminum for these cars. Secondly, being exposed as they are the chances of the pipes being damaged by road debris and rupturing is considerably higher than rubber hoses.
Kurt
@@klassikats Nice one.
Where did you get the hose kit?
There is no kit you just have to buy or make the hoses individually
Kurt
Thank you. And thank you for the video it’s great!
Your welcome
Kurt
Where are you located? What would a job like this cost me? I can ship my car to you!
I am in Flagstaff, AZ you can reach us at contact@klassikats.com
Kurt
U do all that work and start w a used compressor?!?!
Of course, we did not know that the compressor would leak as the system came dis-assembled. Plus we owe it to our customers to do our due diligence and actually confirm a failure and not just throw parts at something in the hopes of fixing it.
Kurt
Absolutely not worth it. These cars were never meant to have AC. Not good on the engine bay, heat generation, just ridiculous. I took all mine OUT.
Totally disagree. You could be driving the the best P car in the world. But sitting there soaking in sweat at 35degrees ? I don’t think so.
I refitted mine to my 73 car. Best thing I ever did. Doesn’t even feel slower on the track!
I agree with Nick, the A/C system is such a minimal drag on the engine and it makes the driving experience so much better especially in the south west where temperatures are well over a 100F. The other thing to remember is that the system comes with an off switch. So if you want to suffer just turn it off.
Kurt