How to: Converting an R-12 Air Conditioner to use R-134a

[Scott B.]

Have you used Freeze 12? I wonder how good it really is?

I need to recharge my A/C - I have 3 cans of R-12, but I only have 3 cans.

 

[mustgofaster]

If you know a carrier I can ship it with, I have a case of R-12.

 

[Tbars4]

Have you used Freeze 12? I wonder how good it really is?

I need to recharge my A/C - I have 3 cans of R-12, but I only have 3 cans.

...I have the freeze12 in my X...My mechanic buddy uses it in all the R 12 vehicles now..

..Mind you, he did a full service on the A/C when he installed it...

 

[okieplayer32]

I had a mechanic put 134a on top of r12 without converting anything, he did nothing but hook on to my system and added the 134a, a few days later the system quit cooling and i took it to another mechanic where he said my system is ruined and that i would have to replace the whole ac system now, is this true and if so is the certified licensed mechanic responsible for this.....

 

[DJakaSmogCop]

Okieplayer, whether the technician who added R134 to your system is responsible (leagally) or not is dependent on what state you reside in. You can contact the better business bureau of your state and check with them. You can also check with the DMV in your state and find out if there are any consumer protection organizations that can assist you. If you happen to be in California, We have the Bureau of Automotive Repair. You can file a complaint with the BAR and they will look into the facts of your complaint and attempt to determine fault and if determined to be in your favor, they will attempt to secure a refund or rework of the repairs.

 

[DJakaSmogCop]

I am getting ready to do a conversion of my 92 xlt ranger. I will be replacing the compressor, accumulator, orifice tube and main hose from compressor to condenser and accumulator.

Can anyone tell me how much oil I should add to the accumulator, the condenser, and the evaporator?

Should I use PAG oil?

What would be the correct amount of R134 freon to use. (intend to have the unit recharged at a local shop, but they wont do it unless I can tell them how much to put in).

Finally, Do I need to remove the condenser to properly flush it?

Thanks for any help.

 

[tcotrel]

Retrofit help needed

I have NO experience as a DIYer on this. Everything on the AC in my 1991 Explorer that can leak is leaking (only has 51K original miles) and the compressor probably needs replacing. It probably won't cost much more to switch over to R-134a than to fix the original R-12 set-up. I have to assume that whatever R-12 was in there (from what the mechanics and temperature of the air with the AC on tell me) has long since gone to punch whatever hole in the ozone layer it was going to punch.

I want to do this on a budget. Who can do it cheap but reliably? Is there a kit/instructional DVD I can use? I know enough not to even think about the fabled $30 conversion kits in a can.

 

[ranger7ltr]

Where I would start for a retrofit to R134A...

Doing a retrofit to R134A from R12 is not difficult but it does require attention to detail...And cheap is not a term in a conversion...R134A needs better cooling at the condensor to remove latent heat from the refrigerant and it does operate at higher pressures than R12 did...

The first thing I would do is find a local shop to rebuild the hoses on your truck...20 year old hoses will not withstand pressures for long even if they look like they just came from a 5th avenue bouquet...I would consider replacing the compressor for the same reasons...The condensor is probably not a serpentine design which allows a longer path for refrigerant to travel through it and dissipate heat to help cool the interior air in the evaporator...Now adding an electric fan to the original condensor can help the cooling issue and actually can help even if you go to a later design condensor...A heavier duty thermal fan clutch would be mandatory to pull max air through the condensor and radiator to keep both cooler...And finally an orifice tube and orings throughout for R134A are needed as well...

Obviously the accumulator will need to be changed and current units support both R12 and 134A so that is not a concern...The evaporator is the only component that does not need to be replaced for this conversion...And remember the refrigerant oil needs to be either pag, ester, or synthetic oil like Polyalpha A[my personal favorite]...

Since your Explorer will be very similar to a later model Explorer the capacity of R134a can be based on that later model Explorer instead of guessing by starting with 60-70% of the R12 capacity when converting to R134A...

Now the cost to do this? Well this is where good shopping might help...Used parts for the condensor and compressor from an R134A would bolt on in place of the R12 parts...Accumulator and orifice tube need to be new and the unknown is the hoses...Old R12 hoses impregnated with mineral oil supposedly stop the flow of R134a molecules through the hoses but using old hoses is living on borrowed time imho...

 

[tcotrel]

Doing a retrofit to R134A from R12 is not difficult but it does require attention to detail...And cheap is not a term in a conversion...R134A needs better cooling at the condensor to remove latent heat from the refrigerant and it does operate at higher pressures than R12 did...

The first thing I would do is find a local shop to rebuild the hoses on your truck...20 year old hoses will not withstand pressures for long even if they look like they just came from a 5th avenue bouquet...I would consider replacing the compressor for the same reasons...The condensor is probably not a serpentine design which allows a longer path for refrigerant to travel through it and dissipate heat to help cool the interior air in the evaporator...Now adding an electric fan to the original condensor can help the cooling issue and actually can help even if you go to a later design condensor...A heavier duty thermal fan clutch would be mandatory to pull max air through the condensor and radiator to keep both cooler...And finally an orifice tube and orings throughout for R134A are needed as well...

Obviously the accumulator will need to be changed and current units support both R12 and 134A so that is not a concern...The evaporator is the only component that does not need to be replaced for this conversion...And remember the refrigerant oil needs to be either pag, ester, or synthetic oil like Polyalpha A[my personal favorite]...

Since your Explorer will be very similar to a later model Explorer the capacity of R134a can be based on that later model Explorer instead of guessing by starting with 60-70% of the R12 capacity when converting to R134A...

Now the cost to do this? Well this is where good shopping might help...Used parts for the condensor and compressor from an R134A would bolt on in place of the R12 parts...Accumulator and orifice tube need to be new and the unknown is the hoses...Old R12 hoses impregnated with mineral oil supposedly stop the flow of R134a molecules through the hoses but using old hoses is living on borrowed time imho...

THANKS. I just assumed all the hoses and most of the other parts would have to be replaced. I accept the idea I will have to spend $$ on the parts. I want to figure out a way to at least save some on the labor.

 

[ranger7ltr]

If you want to save on labor? Do it all yourself...

Swapping the parts onto your truck is easy enough and the orings and seals required just go into the same locations as the old ones come from...

Even if you have never done a/c work, as long as the system is empty, replacing parts is as simple as removing old parts and replacing them with new or newer ones...

If you have not done any a/c work, you probably do not have any a/c gauges or vacuum pumps or specialty tools like that... Once you get the components replaced, take the truck to a local a/c shop for them to install oil in the system, vacuum it down to remove the moisture inside, and then recharge it with R134A... If you have the tools you need to do this, then pour oil in the condensor and accumulator when replacing them, seal up the system asap, then vacuum it down and after checking for leaks charge it by weight of refrigerant...

Your reward either way should be vent temps in the 37-42 degree range...Plus you did most, if not all, of the work involved to fix your a/c...

 

[swansoninlargo]

I want to recharge my 2005 Ford Ranger, and need too know where the Low-Side-
valve is?

 

[MPOster]

Bad Link ---

as warmer weather comes on, there are more and more posts on a/c matters. Many refer to conversion of a pre-94/95 r-12 system over to use r-134a. I have cautioned against simply buying one of the $30 kits and doing it yourself if you have no a/c experience. Simply put, failure to properly clean and flush out all the r-12 residue and mineral oil can, and in time will result in a/c failure. Further, you need to properly evacuate the system prior to recharge. Neither flushing equipment nor a good vacuum pump and gauge set are generally readily available to the home diy person - and shortcuts here can spell disaster. Can it be done at home? Sure. Here's a good link all about it.

http://www.glue.umd.edu/~singletn/web/pages/acconvert.html

happy exploring...

Chris

this link is no longer valid from 2003​

 

[Maniak]

this link is no longer valid from 2003​

It is here now.. (I'll see if I can fix the orig. post)
http://www.explorerforum.com/Singleton/web/pages/acconvert.html

All of the singleton pages that could be found/archived are now hosted on EF and can be found @ http://www.explorerforum.com/Singleton/exp.html

~Mark

 

[ironbandit]

I am coming to this party late, but I have to ask, as I can't find them anywhere else, what are factory specs for the weight of refrigerant that is needed to fully charge a Gen 1 4.0L OHV system? Them's of you that have worked on them simply have to know what these values are, or where to find them. We are working from a 30lb tank of R-134, and are using a digital scale to keep track of how much is leaving the container.

 

[Glacier991]

1st Gens used 1 lb 15 oz of R-12. Use a conversion chart to figure out your needed load.

**Note edited to show corrected amount**

 

[ironbandit]

Thanks, but I got word from a friend that the Gen-1 4.0L OHV Explorers take 36 oz of R-134A to fully recharge. This is, of course, after replacing the compressor and desiccant bottle, flushing the rest of the system with brake cleaner and compressed air. The system will then undergo a 16-hour evacuation, using a Robinaire pump.

 

[Glacier991]

Well, you choose what you want to choose, but I think 48 OZ is WAY over what is needed. read up this thread where others used something under 2 lbs. If you are hellbent of seeing if 3 lbs works, add 28 oz and start checking vent temps...as you continue to add.

Maybe if you added a 134 system condensor it might take more than 2 lbs... but... just adding 3 lbs to the system could flood the compressor and cause damage.

 

[ironbandit]

Thanks, but I got word from a friend that the Gen-1 4.0L OHV Explorers take 36 oz of R-134A to fully recharge. This is, of course, after replacing the compressor and desiccant bottle, flushing the rest of the system with brake cleaner and compressed air. The system will then undergo a 16-hour evacuation, using a Robinaire pump.

Glacier:

Where did I state anything about 48 oz? I've seen figures from 22 to 36 oz, with stops at 30 in the threads. Today, we had to remove the compressor to put oil in it. It was determined by a call to tech support of the seller that I got the compressor and drier bottle from, there was no oil in the compressor when it was shipped. The system then underwent a 2.5 hour evacuation, followed by a charge of 26 oz of the R-134A, before the high pressure read 250PSI, and the low side at 100PSI. We determined that a lot of fluid is in the system, and it should work itself out over the next cuppla weeks. It is cooling the incoming air, but not frosty, so I figure that it is working.

 

[ironbandit]

Good news, Chris et al:

Even though, we put liquid into both the low and high side fittings with the engine not running, followed by vapor/gas into the high side, the system has settled down to 40+ PSI on the low, and 250 PSI on the high. A slight added charge, 3-4 oz, may be needed to move the low side up to 50+ PSI, and this is all with 26 oz, or 1 lb 10 oz, in the system so far. 36 oz may be too high, but the system would not take that much anyway, it stopped us at 26.

 

[Fatty explorer]

nice thread