1989 F-150 R-12 to R-134a
Thread Starter
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Mountain Pass
Joined: Mar 2024
Posts: 111
Likes: 12
From: MN
1989 F-150 R-12 to R-134a
What do I need to swap it over. I made the mistake of putting R-134a in my R-12 system. Old owner said he swapped it but I learned I was wrong. It was not swapped. Now my system has R-134a in it. The compressor kicks on and works. But I would like to switch it over to a better system. What do I need to have it work nicely with R-134a? So far I think I would a need a Compressor, Accumulator, Orifice Tube and O rings. Should I get new lines for it..? Not sure about these systems. Also how do I remove the lines with the refrigerant in it? Do I just carefully remove the lines? I'm not sure if the system leaks.
Hotshot
Joined: Jul 2020
Posts: 10,453
Likes: 2,630
From: Near Salt Lake City
You need an "ester" oil to make the 2 oils compatible
You will never get all of the R12 mineral oil out
The ester will make the 2 oils, not form acid, and destroy your system
I'm wondering if any of you have ever been to A/C school?
Speaking to those of you who think you can simply flush the system and replace a part, any part
Buy a retrofit kit that has the fittings and the ester oil, add the oil and add the r134a after evacuating it
You will never get all of the R12 mineral oil out
The ester will make the 2 oils, not form acid, and destroy your system
I'm wondering if any of you have ever been to A/C school?
Speaking to those of you who think you can simply flush the system and replace a part, any part
Buy a retrofit kit that has the fittings and the ester oil, add the oil and add the r134a after evacuating it
Lead Driver
Joined: Sep 2002
Posts: 9,539
Likes: 2,030
From: North Texas
A small tube condenser or parallel flow will help a pile with heat rejection for the swap and make your system more efficient.
38oz of 134
11oz PAO 68
Red FOT
But if your compressor works, I would just run it as-is but yes 134 and 12 use diff oils.
EDIT - some engines had different cooling fans available, 4.9 for sure. Five versus seven blade, the more across the condenser the better. Either small block can run a 302HO fan over the steel one, moves quite a bit more air!
Obviously verify the fan clutch is good and the shroud is installed.
38oz of 134
11oz PAO 68
Red FOT
But if your compressor works, I would just run it as-is but yes 134 and 12 use diff oils.
EDIT - some engines had different cooling fans available, 4.9 for sure. Five versus seven blade, the more across the condenser the better. Either small block can run a 302HO fan over the steel one, moves quite a bit more air!
Obviously verify the fan clutch is good and the shroud is installed.
Last edited by Hit Man X; May 31, 2026 at 08:26 AM.
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Lead Driver
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i ain't rite
Joined: Mar 2005
Posts: 65,507
Likes: 5,563
From: Marlboro Mental Hospital.
You need an "ester" oil to make the 2 oils compatible
You will never get all of the R12 mineral oil out
The ester will make the 2 oils, not form acid, and destroy your system
I'm wondering if any of you have ever been to A/C school?
Speaking to those of you who think you can simply flush the system and replace a part, any part
Buy a retrofit kit that has the fittings and the ester oil, add the oil and add the r134a after evacuating it
You will never get all of the R12 mineral oil out
The ester will make the 2 oils, not form acid, and destroy your system
I'm wondering if any of you have ever been to A/C school?
Speaking to those of you who think you can simply flush the system and replace a part, any part
Buy a retrofit kit that has the fittings and the ester oil, add the oil and add the r134a after evacuating it
and i would NEVER convert a R-12 system to R134-A
the R-12 system will freeze you out of the truck.
Thread Starter
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Mountain Pass
Joined: Mar 2024
Posts: 111
Likes: 12
From: MN
Unfortunately I cannot get R-12. Expensive and you need a license to get it if I can recall correctly. If I could find some I would love to refill it with R-12.
Thread Starter
|
Mountain Pass
Joined: Mar 2024
Posts: 111
Likes: 12
From: MN
A small tube condenser or parallel flow will help a pile with heat rejection for the swap and make your system more efficient.
38oz of 134
11oz PAO 68
Red FOT
But if your compressor works, I would just run it as-is but yes 134 and 12 use diff oils.
EDIT - some engines had different cooling fans available, 4.9 for sure. Five versus seven blade, the more across the condenser the better. Either small block can run a 302HO fan over the steel one, moves quite a bit more air!
Obviously verify the fan clutch is good and the shroud is installed.
38oz of 134
11oz PAO 68
Red FOT
But if your compressor works, I would just run it as-is but yes 134 and 12 use diff oils.
EDIT - some engines had different cooling fans available, 4.9 for sure. Five versus seven blade, the more across the condenser the better. Either small block can run a 302HO fan over the steel one, moves quite a bit more air!
Obviously verify the fan clutch is good and the shroud is installed.
Fleet Mechanic
Joined: Oct 2025
Posts: 1,768
Likes: 388
How would a vacuum pump remove all of the oil and refrigerant? Isn't it hard for a pump to remove oil from a system? Would be nice to run the original compressor and lines. May be the case that I have to order compressor and lines with the kit. The compressor kicks on but then shuts off. Probably because the system has R-134a in it instead of R-12. As I said in the OP.
i ain't rite
Joined: Mar 2005
Posts: 65,507
Likes: 5,563
From: Marlboro Mental Hospital.
all you need to buy refrigerant is an EPA 609 certificate. cost is around $25. you take it online, and can have the book with the answers in front of you while taking the test.
Lead Driver
Joined: Sep 2002
Posts: 9,539
Likes: 2,030
From: North Texas
Exactly on the 609, plus you can learn something and answer your own questions
It flips on and off as the charge is probably super low. Go buy a nice gauge set from Mastercool or Yellow Jacket so you can see what os going on. Cheapo HF ones will work in a pinch
It flips on and off as the charge is probably super low. Go buy a nice gauge set from Mastercool or Yellow Jacket so you can see what os going on. Cheapo HF ones will work in a pinch
More Turbo
Joined: Feb 2022
Posts: 655
Likes: 106
From: New Dominion, PE
You need an "ester" oil to make the 2 oils compatible
You will never get all of the R12 mineral oil out
The ester will make the 2 oils, not form acid, and destroy your system
I'm wondering if any of you have ever been to A/C school?
Speaking to those of you who think you can simply flush the system and replace a part, any part
Buy a retrofit kit that has the fittings and the ester oil, add the oil and add the r134a after evacuating it
You will never get all of the R12 mineral oil out
The ester will make the 2 oils, not form acid, and destroy your system
I'm wondering if any of you have ever been to A/C school?
Speaking to those of you who think you can simply flush the system and replace a part, any part
Buy a retrofit kit that has the fittings and the ester oil, add the oil and add the r134a after evacuating it