R12 to 134. Whats really needed to do this swap for a great working system. All parts needed?

Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.

Hunter79764

Full Access Member
Joined
Sep 1, 2021
Posts
344
Reaction score
536
Location
Grand Prairie, TX
First Name
Shawn
Truck Year
1987
Truck Model
Suburban V20
Engine Size
350
It certainly can be that easy. Again, if the system is plenty good with R12, it ought to be fine just swapping to 134 with compatible materials etc. You will lose maybe 10-20% due to the refrigerant characteristics, but in a single cab it should be fine.

But I can tell you my Monte Carlo was mostly enough with stock R12, but it needed to run on Hi/MAX at anything over 95° outside, and as long as you drove long enough at high enough speed, it would keep it cool enough to be comfortable. Window tint helped, since I was never able to park in the shade consistently. That was west Texas where 110° was normal, but there is very little humidity. When I switched to 134 on a straight swap, it just wasn't cutting it, especially at idle or stop/go traffic. Adjusting the pressure switch helped so that I got cold vent temps, the condenser was the tube/fin type, and I did not change the orifice. Adding an electric fan made it where my wife was willing to ride in it, but still not "good" in the really hot times.

I abandoned the AC in that one with the engine swap, but if/when it gets a redo, you can bet that I will upgrade the condenser, switch the orifice tube, dial in the low pressure switch, and run electric fans (already do, but I'll keep them for sure) if I want it comfortable. The Suburban will get a similar treatment, microchannel condenser, blue or even red orifice tube, and dial in the low pressure. I plan to keep using the Suburban as a vacation vehicle down near Galveston, and I'm sure you are well aware that Houston area puts a certain extra load on a vehicle's AC...
 

SlickGTP

Full Access Member
Joined
Feb 24, 2011
Posts
787
Reaction score
124
Location
Houston, TX
First Name
John
Truck Year
1973
Truck Model
C10
Engine Size
454
For those of you in the storm, I hope all is well. We took a good hit and still out of power. Lots of damage. Hope all is well. SUPER SCARY SH&T.

I hope you have power back by now... We've been relatively lucky being out on the west side.

Thanks for the thread! I've been meaning to see what it would take to put the A/C back in the Ol' Girl. Figured a minimum of new hoses, rebuild the compressor, and flush the system, but wasn't sure what else I might need.
 

91burb2500

Member
Joined
Jun 8, 2024
Posts
46
Reaction score
49
Location
Plantation, FL
First Name
Joey
Truck Year
1991
Truck Model
Suburban R2500
Engine Size
5.3
The parallel condenser was the missing piece on my Suburban, it kicks ass now. Pretty much sucked before once the temps got into the upper 80s/90s with 80% humidity of south Florida. I did do the Sanden compressor as well, but the R4 would’ve worked just as well I imagine with the new condenser. I was just over the lack of reliability even from AC Delco ones and the power loss that was noticeable.
 

bucket

Super Moderator
Staff member
Super Moderator
Joined
Aug 3, 2010
Posts
30,591
Reaction score
28,780
Location
Usually not in Ohio
First Name
Andy
Truck Year
'77, '78, '79, '84, '88
Truck Model
K5 thru K30
Engine Size
350-454
The parallel condenser was the missing piece on my Suburban, it kicks ass now. Pretty much sucked before once the temps got into the upper 80s/90s with 80% humidity of south Florida. I did do the Sanden compressor as well, but the R4 would’ve worked just as well I imagine with the new condenser. I was just over the lack of reliability even from AC Delco ones and the power loss that was noticeable.


That's very true. Getting a good R4 in the last 10-15 years is about impossible. And you definitely feel them kick on and off if you have a stock or very mild engine.
 

Forum statistics

Threads
44,391
Posts
956,287
Members
36,683
Latest member
aim410x
Top