Packard Forum Index » Post-War (1946-54)

what kinda coolant should i put in mt 1951 200 delux???

Your normal green antifreeze will work just fine, mixed at 50/50 for most climates, adjust accordingly.

Hi there,

Over here we are advised to use blue coolent as the green stuff is not good for old gaskets. Some people here say that their vintage cars leak more with green coolant rather than blue. I have really never noticed a difference myself.

Pat.

the color is just a dye. What's in the blue and green versions (both are glycol-based)?

Don't have specifics but the primary differences between the red and green and possibly the blue which I'm not familiar with are the corrosion-inhibitor packages and possibly the use of propylene glycol versus ethylene glycol. The former is much more environmentally acceptable, in fact being manufactured and available in an edible food-grade whereas ethylene glycol is quite toxic. The changes in anti-corrosion packages are primarily a result of the majority of modern engines being primarily of aluminum alloys, and radiators primarily plastic tanks on aluminum cores rather than copper. Thus the traditional anti-corrosion packages aimed at copper radiators and cast iron engines (the green stuff) is not optimized for modern engines. Whether the reverse is true (modern antifreezes not optimum for cast iron engines) I don't know, but I continue to use the original "green" formulation in my cars with cast iron engines and copper radiators. The traditional anti-corrosion packages were primarily inorganic silicates and organics of the tolytriazole type.

the "best" to use would be the "mixes with any color" that you will find at most any good parts store. that way it won't matter if you are running low and can only find one or the other. You DO NOT WANT TO MIX the other two!