A/C Recharge for R12

[Felix_29]

Hello all, i'm wondering if anyone has step by step instructions with photo's or perhaps a video of how to recharge the A/C in the Delorean with the R12 cans you can buy at the auto supply store? I have seen this done a couple of times but its been too many years for me to remember how to do it exactly. I'm on the original R12 system.

[SS Spoiler]

Good luck finding R-12......

[Michael]

You are probably seeing a R12 replacement like jonsens but even that stuff is hard to come by anymore. Finding soneone with an r12 machine will be a trick too. Most shops don't mess with it these days. I bought an r12 machine and about 20 cans a few years ago and I ended up selling it all when I switched over to r134 and I am glad I did. Vent temp differences are not noticable.

Just an assumption but judging by your question I don't think you should be doing this job yourself. Unless you know what you are doing, you can cause some injury to yourself as well as jack up your car.

[hippieman9]

Hello all, i'm wondering if anyone has step by step instructions with photo's or perhaps a video of how to recharge the A/C in the Delorean with the R12 cans you can buy at the auto supply store? I have seen this done a couple of times but its been too many years for me to remember how to do it exactly. I'm on the original R12 system.

go on Ebay or Amazon and get red Tek. It is compatible with R12 and is simple to recharge. It works great and no need to retro fit anything. The kit also comes with a can of sealer if you have a small leak too.

[Andrew]

As a CFC, R12 has been phased out as part of the Montreal Protocol. For those who are too young to remember, CFC's and the Ozone hole were the fad panic of the 1980's and early 1990's. Forget nuclear weapons...hairspray was going to kill us all!!! Pursuant to legislation that was enacted in 1991, R12 hasn't been available in retail outlets for customer purchase since 1991 or 1992. There was a big run on small cans of R12 at the retailers the final season when cans were available. The final year of R12 in new US vehicles was 1993. All production / importing of R12 to the US ceased on December 31, 1995. The cost of R12 seemed to peaked in the early 2000's when vehicles that still used R12 were in general circulation. As the cost of R12 went up, R134A retrofits became pretty common. In the meantime attrition has taken its toll on pre-1994. As of 2018 most of the pre-1994 cars have been converted to R134A or are no longer in circulation. Interestingly, the price of R12 seems to have leveled-off / decreased in the past few years. I have had success finding R12 on Craigslist. Most of the cans that I have found are being sold by people who stocked up during the 1992 retail phase-out only to have the cans sit in their garage / basement for the past 25 years (long after their sold / junked the 1988 Pontiac 6000 that they bought the R12 for in the first place.

Be aware the purchase of R12 is regulated by the EPA. To purchase R12 for personal use, you are required to have an EPA 609 certification. However, you can buy cans of R12 if you provide a signed statement to the seller that you are buying it for the purpose of selling it to a EPA 609 licensed tech. The good news is that you can get an EPA 609 certification via an online, open-book test for $15 and the certification never expires. I have done exactly that and carry my card in my wallet. In the years that I have been buying R12, I've never once had a seller ask me for my EPA 609, but I'd rather be safe than sorry. I've paid between $15 and $20 per can. Some sellers will give you a volume discount if you buy their entire lot of cans. When purchasing cans from Craigslist, check the labels on the cans to make sure it is real R12 and feel the weight of the can to determine if it still feels full...these cans are now over a quarter century old and have may have rusted or leaked in storage.

In short, check your local craigslist with search terms such as "R12" "R-12" "Freon." However, I suspect that the ban on CFC's will be lifted / relaxed within the next couple years...in fact I'm surprised Montreal protocol hasn't already been scrapped...so don't invest your life savings in an R12 stockpile, because it might be back on the shelf of your local Walmart / Autozone by next summer ;-)

Andrew
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[SS Spoiler]

Make friends with your local appliance refrigerator
repairman. I was able to score a 30 lb drum of
reclaimed, filtered R-12 for a 100 bucks. He only
wanted 75 but I told him it was worth a 100 to me..

[WHO1DMC]

And now they are going to this 1234yf stuff it's supposed to be better for the environment but it's flammable. Woo-hoo another way die in a car.

[Bitsyncmaster]

And now they are going to this 1234yf stuff it's supposed to be better for the environment but it's flammable. Woo-hoo another way die in a car.

If it's flammable, just use propane also sold as R12a.

[Nicholas R]

If it's flammable, just use propane also sold as R12a.

To clarify, don't just use propane (as in, don't connect your AC compressor to your BBQ grill propane cylinder and fill the system :wink:)

R12a is a hydrocarbon blend that attempts to mimic the evaporation and condensation pressures consistent with traditional automotive refrigerants (R12/R134a). With that said, it will certainly be just as flammable as any hydrocarbon fuel (since it's mostly propane).

[Bitsyncmaster]

To clarify, don't just use propane (as in, don't connect your AC compressor to your BBQ grill propane cylinder and fill the system :wink:)

R12a is a hydrocarbon blend that attempts to mimic the evaporation and condensation pressures consistent with traditional automotive refrigerants (R12/R134a). With that said, it will certainly be just as flammable as any hydrocarbon fuel (since it's mostly propane).

+1
If it's a blend of gasses, you have to charge via liquid with a large container but if using a whole can I guess your can charge via gas. The reason is each blend will not convert to gas at the same pressure and temperature. Charging via liquid has to be done very slowly so you don't lock up the compressor. The new R410a now used in home systems and replaces R22 is a blend you charge via liquid.

[Felix_29]

Thank you for you insights everyone. How do I find the low side of the A/C system for the proper hook up?

[WHO1DMC]

Should have a blue cap on it. If not it will be the small connection on the left aka the low side.

[Felix_29]

Mine doesn't have the blue cap. I have two green ones. So i want the left one. The one that has the two hoses plugging in directly underneath it?

[Bitsyncmaster]

The low side is the larger hose. But I think DPI hose sets are the same size for low an high sides.

[WHO1DMC]

The back of the compressor should look like this. If using a can with a hose with a connection it should only hook up with its mate.

[Felix_29]

I dont suppose anyone could post a photo that points to where I am supposed to go.

[Felix_29]

Disregard my last post. Thank you. So i have two green caps. I need to use the one on the left. In your case. The silver one. The kit came with a retro fitting to allow the hose to attach to it. What worried me was that it also threads to the right port as well. So i need to totally ignore the right side port.

[WHO1DMC]

For putting freon in. Yes

[WHO1DMC]

Ok is this system still on R12? If so you need to have that taken out. You shouldn't put 134a in with R12. And the compressor my only last a short time because it's not made for it. Took the leap myself and had to put in a new one.

[Felix_29]

Yes, the system is on R12. I am using an aftermarket refridgerant. It is compatible with R12 system.

[Bitsyncmaster]

Fittings for R12 and R22 are the same for high and low sides. It was the R134 that made different fittings. The reason was to reduce the amount of gas vented when the hoses were disconnected and attached. They also made them different sizes so as not to attach the wrong charge hose.

[Felix_29]

I understand. So now I am sure. I attach the R12 fitting to the cap on the left side of the system.

[Felix_29]

Ok, so I didnt end up recharging the system. When I attached the r12 adapter and hooked up the regulator with the can. I gotba regulator reading of 58PSI. Just at the blue meets yellow. I take that as it doesnt need a recharge. I dont understand why my ac is not blowing very cold. The ac belt is turning when the car is on. Any ideas?

[WHO1DMC]

To show true pressure the compressor has to be running. And that is how you ad refrigerant it sucks it in. When running if my memory serves me it should be 30 to 35 psi.

[Michael]

Ok, so I didnt end up recharging the system. When I attached the r12 adapter and hooked up the regulator with the can. I gotba regulator reading of 58PSI. Just at the blue meets yellow. I take that as it doesnt need a recharge. I dont understand why my ac is not blowing very cold. The ac belt is turning when the car is on. Any ideas?

Was the engine or AC system off when you connected your hose? I really think you need to heed my original advice, this is not a job for someone with limited knowledge on AC systems.

[Felix_29]

The car was off when I hooked up the regulator.

[Michael]

The car was off when I hooked up the regulator.

Then you have no clue what the actual low pressure was.

[opethmike]

Take the car to an A/C shop. Seriously.

[Felix_29]

Well it is obvious you guys do know more than I do about this. You guys obviously learned this a/c stuff somehow yourselves. How would you feel if someone said to you "Don't do this job yourself" or "take it an a/c shop. seriously". I'm not sure why you feel i'm not capable of learning what you know... I won't learn anything if I keep taking the car into a shop every time it needs something. I'm trying to be learn more about my car and be cautious at the same time. I think i'm doing the right thing by taking it slow and asking questions. I'm not totally green to this. I only lack experience. I thought that was the point of this forum. For owners to help owners. I do appreciate the help I have received on this thread.

[Bitsyncmaster]

When charging the AC system, normally you connect a set of gauges to high an low pressure sides. Those gauges have a third hose that connects to the charging tank or vacuum compressor. The gauge set has two valves that open that third hose to the low and or high pressure side. So people are concerned if you open the wrong valve during your charging the charging tank could blow up and injure you.

When charging your system, the tank holding the refrigerant has gas drawn into the running AC system. That tank has liquid refrigerant and the system draws gas if the tank is held upright. That change of liquid to gas make the tank get very cold and the tank pressure drops. So with the small "tank" cans you normally put that can in hot water held upright so it continues to move the gas from the tank into the AC system.

So what do you have for a gauge charging hose system?

[Nicholas R]

You should really spend an hour or so watching A/C recharging videos on youtube. You need to understand what you're looking at, and the differences when the engine is running vs. not running, the compressor cycling vs. not cycling, etc., as well as what you should expect from the gauges. There's nothing overly specific to the DeLorean that say you can only get your information from this forum. It's good to ask specifics here, but overall AC theory (which you need to learn) is consistent across all cars.

The concern you see expressed in this thread is that you will damage something, or worse, hurt yourself. It's not personal. There are extreme pressures at play here. Simply attaching a can of refrigerant to the wrong side of the compressor could cause it to explode in your hand. On a car converted to R134 this is much less of a concern because a low pressure side charging hose wont fit on a high pressure side fitting. However, being that your car is still R12 with the same fittings on both the high and low sides, this is a very real possibility if you don't know what you're doing.

Similarly, overcharging the system can damage the compressor due to pressure extremes. Charging too fast can damage the compressor, as the liquid can enter the cylinders instead of a gas, and the liquid can also wash out the compressor lubricant. Not having enough lubricant in the system can damage the compressor.

There are times when you can jump into a car project with no knowledge and learn as you go. This may be one of those cases, but only provided that you understand the risks associated and have done your homework. In the end, no one on this forum is going to take responsibility if you hurt yourself or the car. Only you can be responsible for yours and the car's well being.

[Ron]

+1


Well it is obvious you guys do know more than I do about this. You guys obviously learned this a/c stuff somehow yourselves. How would you feel if someone said to you "Don't do this job yourself" or "take it an a/c shop. seriously". I'm not sure why you feel i'm not capable of learning what you know... I won't learn anything if I keep taking the car into a shop every time it needs something. I'm trying to be learn more about my car and be cautious at the same time. I think i'm doing the right thing by taking it slow and asking questions. I'm not totally green to this. I only lack experience. I thought that was the point of this forum. For owners to help owners. I do appreciate the help I have received on this thread.
What I think you are missing is that, when the compressor is not running, the pressure depends on the refrigerant's temperature, NOT how much refrigerant there is in the system, as long as there is a minimum amount present; e.g. When allowed to sit and settle to the ambient temperature, one can in the system would show the same pressure as 3 cans would. So, WRT amount, the only thing that the 58psi you read tells you is that there is some there. WRT pressure, it tells you that there is enough for the low pressure switch to send power to the compressor clutch. So, when you turn on the AC, the clutch should be engaging (even if very briefly). If not, the clutch's coil and/or electrical control has a problem...

OK- Since you said, "I don't understand why my ac is not blowing very cold. The AC belt is turning when the car is on.", I assume the clutch is engaging, else it would not be cold at all. The poor output temps can be caused by anything from too low/high refrigerant charge to vent control. The charge is a good bet, but you would need a set of gauges to safely continue at this point AND get it right, as others have said. If you make a mistake and put more in it, due to the characteristics of refrigerants mentioned etc, it may work fine until a hot day (or future problem) comes along and the resulting overcharge damages something...or someone.

...Check out the link the Resources Section HERE (http://dmctalk.org/showthread.php?7921-AC-Pressure-Charts-Reading-Gauges-(R12-and-Retrofit)) then get your hands on a set of gauges, and hang in there!

[NckT]

Always wear personal protective equipment (PPE) when dealing with refrigerant. Full safety eye goggles that seal around the face is a must at the very least. Refrigerant coming out under pressure can also freeze skin, as well as asphyxiation....

I'll assume you'll read up on working safely with refrigerant and not take this lightly. You only get one set of eyes....

Good luck, be safe, be seeing you :)

[Felix_29]

So I hooked up the regulator to the system. Turned the car on. Set the A/C to max it can go with highest fan speed. The regulator would drop into the blue around 20PSI everytime the A/C clutch would spin. And when it stopped it would go back up to about 60PSI. This just happend over and over again like that until I stopped the engine. My car's A/C Clutch always starts and stops constantly like every 5 seconds. Is that normal? I have included a picture of the kit I bought. Only difference is I don't have the stop leak can.

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[Ron]

That says the system is probably low. But, again, you can not tell how much nor when there is enough with the gauge you have.
You need to take it to a shop and have the system checked to confirm then evacuated and recharged with the spec amount, or, use the method I mentioned above, in which case you need these:

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[kings1527]

So.....AC work. I'm a firm believer that if you're the kind of person that can pick up a book and/or look at videos on YouTube, then you can teach yourself how to do this. And let's be honest: ever take a good look at the people who do this kind of work for a living in a shop? Do they give off a cardiologist or astrophysicist vibe to you? No? Then you can do it, too.

The DeLorean utilizes an cycling clutch orifice tube (CCOT) based system which was popular for the time period, specifically in GM cars (and then GM bought Harrison Radiator, who had designed the heating/AC system in the DeLorean). Why's that important? Because the guts of the system are identical between GM cars of that time and the DeLorean. That being said, this book is outstanding for our cars:

https://www.amazon.com/Automotive-Heating-Conditioning-Systems-Manuals/dp/1563923815/ref=pd_sim_14_4?_encoding=UTF8&pd_rd_i=1563923815&pd_rd_r=b3d217f1-8b1e-11e8-acf3-4d007e1e88bd&pd_rd_w=464HS&pd_rd_wg=yMBh1&pf_rd_i=desktop-dp-sims&pf_rd_m=ATVPDKIKX0DER&pf_rd_p=2610440344683357453&pf_rd_r=AMVHB5PPD6DKHFC2DZWA&pf_rd_s=desktop-dp-sims&pf_rd_t=40701&psc=1&refRID=AMVHB5PPD6DKHFC2DZWA

Hopefully that above link works. Once you understand what all of the major components do (orifice tube, evaporator, condenser, accumulator, high side/low side lines, compressor), then start understanding the process that everyone's referring to. And there's a lot to be said for process, such as removing moisture from the unit and why it's important to use a new accumulator every time you open the system. This guy does a great job of showing you the process of filling:

https://www.youtube.com/watch?v=lglPJuBXVeE

A few points from above postings:
1) R12 is not hard to find and cost seems to have come down some over the years, probably because demand has decreased once cars that use R12 are becoming fewer. If you have an R12 system, consider keeping it R12. It doesn't take a lot to maintain things once you get it all dialed in. I last refilled my system with R12 over 4 years ago and aside from my original high pressure cutout switch going out a couple of weeks ago, it's been flawless. And cold.

2) Be VERY careful using anything that has some type of "leak stop" in it. A total mess on many levels, potentially.

3) Again, this is a VERY common AC system. This wasn't something that was so unique or indigenous to the DeLorean. Overall, the theory of AC is very simple once you learn it, the components are very simple to understand as far as their roles are concerned, and having the right equipment (such as manifold gauges and an AC vacuum) are key.....KEY....to doing things right. Also, in terms of being brand new to AC work, it's MUCH easier to start off with a completely empty system and a new accumulator and fill it from there based on weight rather than diagnose the pressure readings. That's provided you are leak-free and the system can hold a vacuum.

You've got some time to put into this but the info's out there and people here will help you. But getting a solid, base-level knowledge is the first step.