Coolant for '73 BB

[LONNIE WIGGINS]

My brother's '73 BB underhood "restoration" is nearing being completed.

I put that in quotation marks as although the car has about 47K miles and is totally original outside the engine compartment, he had the bright idea in 1976 of pulling the original engine and putting in an LS6 service block with the LS6/LS7 iron open chambered service heads, L88/ZL-1 intake with aftermarket air plenum hood....you get the idea. Fortunately, as "project manager" I won the battle and the headers he had installed were replace with repro factory jet hot coated manifolds - maybe now the inside of the car won't feel like a pizza oven.

Anyway....we're ready to charge the factory A/C....the compressor is original with all original decals - I made sure it wasn't replace or butchered. My question is, is there a better coolant route to go with this setup than R12? I know we could switch to R134....but there are some other coolants out there that I really don't know anything about. Since the motor isn't original, I don't mind a few "different" fittings, if it's the right way to go otherwise. Suggestions? Thanks.

[Joe L.]

Re: Coolant for '73 BB

Lonnie-----

You're actually talking about REFRIGERANT here and not coolant. Actually, if it were me, I would use only R-12 in a system of this old design. I wouldn't attempt to convert it, at all. R-12 is expensive these days but you don't really need all that much for a complete system fill. If the system is in good repair, that charge should last a long time, too.

[Joe L.]

Re: Coolant for '73 BB

Lonnie-----

You're actually talking about REFRIGERANT here and not coolant. Actually, if it were me, I would use only R-12 in a system of this old design. I wouldn't attempt to convert it, at all. R-12 is expensive these days but you don't really need all that much for a complete system fill. If the system is in good repair, that charge should last a long time, too.

[Lee S.]

Re: Coolant for '73 BB

I did an overhaul of the AC system on my 1974 Coupe (LS4) and chose to stay with R12. It is readily available on e-bay. Many sellers do not require documentation.

I paid $80 for a 4 can case which is more than enough to charge the system. After I was confident all of the system leaks were repaired and it held a vacuum for 30 minutes, my local Chevrolet Dealer charged the system using my R12.

Beleive me, in the setup you are building you want all of the AC you can get (and insulation).

Regarding R134A, I have had very good success using the Interdynamics conversion kits readily available at Advance Auto Parts, etc. I have used them on my kids cars with good results.

[Lee S.]

Re: Coolant for '73 BB

I did an overhaul of the AC system on my 1974 Coupe (LS4) and chose to stay with R12. It is readily available on e-bay. Many sellers do not require documentation.

I paid $80 for a 4 can case which is more than enough to charge the system. After I was confident all of the system leaks were repaired and it held a vacuum for 30 minutes, my local Chevrolet Dealer charged the system using my R12.

Beleive me, in the setup you are building you want all of the AC you can get (and insulation).

Regarding R134A, I have had very good success using the Interdynamics conversion kits readily available at Advance Auto Parts, etc. I have used them on my kids cars with good results.