Proper Coolant for a 1973 Corvette

[Timothy K.]

Thinking of changing the coolant in my '73 since it's been longer than I remember. I'm out of the old type of coolant GM (pre-1982) offered. Does GM still offer the proper green coolant, if so, does anyone have the PN? The PN on my container doesn't even come up any longer. If not, any strong recommendations?
Thanks-
Tim (26883)

[Joe L.]

Re: Proper Coolant for a 1973 Corvette

Thinking of changing the coolant in my '73 since it's been longer than I remember. I'm out of the old type of coolant GM (pre-1982) offered. Does GM still offer the proper green coolant, if so, does anyone have the PN? The PN on my container doesn't even come up any longer. If not, any strong recommendations?
Thanks-
Tim (26883)

Tim------


The GM coolant (green-ethylene glycol base) for your vehicle is currently GM #12378560, aka Delco 10-5034. However, I'm pretty sure it's exactly the same as Prestone green which is easily available.

However, for Corvettes with copper/brass components in the cooling system (like your radiator and heater core), I recommend using Zerex G-05. This is easier on the solder joints of those components. The Zerex G-05 meets GM standards 1852M and 1899M applicable to your application.

[Leif A.]

Re: Proper Coolant for a 1973 Corvette

I agree with Joe. Mix the Zerex G-05 in a 50/50 ratio with distilled water.

[Mark E.]

Re: Proper Coolant for a 1973 Corvette

Zerex also makes "Original Green" which meets 1825M and 1899M, and is likely similar in constitution to the GM product Joe mentions and the factory fill.

Although I've never used it, I like the recommendation of Zerex G-05, which according to Joe, may be easier on the cooling system.

Question: Is coolant color checked during Flight judging (G-05 is yellow)? Starting in 1973, coolant is visible in the coolant recovery tank.

[Duke W.]

Re: Proper Coolant for a 1973 Corvette

I agree with Joe. Mix the Zerex G-05 in a 50/50 ratio with distilled water.

Ditto, and anywhere between 50 and 60 percent G-05 with distilled water.

...don't know about the judging issue (refer to the JG), but as Joe said, the fine print on the label says it meets GM 1825M and 1899M.

Duke

[Anthony C.]

Re: Proper Coolant for a 1973 Corvette

My 75 has original radiator. Should I use prestone or Zerex G-05

[Joe L.]

Re: Proper Coolant for a 1973 Corvette

My 75 has original radiator. Should I use prestone or Zerex G-05

Anthony------

I'd recommend the Zerex G-05 for your 75.