198plus

I'm wanting to change my 78 Corvette air cond back to R12. Are there any problems when changing it back to R12 from R134 ??

VCuomo

You mean besides finding R12 to fill your system with?

198plus

I can get R12, I'm just bought my car and someone had swapped it over to 134. Looks like all they changed were the fitting for 134. I'm just not happy with the 134 and really would like to change it back to R12 and wasn't sure what was involved in swapping it back over.

7T1vette

Either refrigerant will do the job... IF your A/C system is in good shape AND the plenum isn't filled up with debris [preventing good air flow]. You would need to run the A/C system a little 'harder' if it had the 134a stuff in it {it's not as efficient a coolant as R-12}, but that should be the only difference. Have your system checked out before you go to the trouble of changing the system back to R-12.

wisoutlaw

Most times with the 134 conversions you need a slightly larger condenser or use a parallel flow condenser. Since 134 is not as "efficient" as 12, the larger condenser or more efficient parallel flow condenser makes up for the slight efficiency loss.

terry82

I think you will have a problem changing the connections back over to r12 .the 134 connections are glued on .

qwank

they screw on

Wrecked82

Some of the screw ons have burrs built in so you can't take them off without damaging the original fitting.

terry82

well then let us know how it goes.

68/70Vette

I dissembled the stock AC in my 1970. The AC plenum was about 1/4 full of leaves, etc. Also, on a C3, the cold chamber AC plenum is a whopping 1/2 inch away from the exhaust manifold (on a Big Block). It's not insulated, maybe a 3/8 inch thickness of plastic fiberglass....obviously a tremendous parasitic heat load. Actually over the years, I didn't see until I removed the engine, the plenum had cracked and the cold air plenum was blowing some cold air into the engine compartment. Before you get fussed with the refrigerant issue, check out the integrity of the basic air conditioning system.

Also, after 1969, GM reduced the amount of insulation in the cars. The 68 and 69's had a lot of more cabin insulation against engine firewall heat and underbody (floorpan) heat. It's relatively easy and cheap to add this extra insulation to your post 1969 Corvette. Vendors have the parts necessary. I've since added a lot of insulation on the passengers side of the firewall since I have the dash board and dash panels removed.

I've completely removed the factgory AC. In it's place is a Vintage Air modern AC system that fits entirely under the passenger's dash panel.
The evaporator is now inside the passenger compartment...no longer along aside the 1000 degree F exhaust manifold.