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

I have not had any problem with the cooling of my 41 super eight but when I look into the radiator I do not see any coolant ,. I think this is just because of the inner construction of the tank. I still top it off to the point when I can see coolant and shortly after the car is started it expels the amount I added. I don't want to repeat this but I want to always be sure it has the recommended capacity. I like to keep things original but I recently talked with a Packard owner that has. A 41 that someone added an overflow tank. Has anyone attempted this , any suggestions ?? Thank you

There needs to be a bit of space (air gap) for the fluid to expand when hot, or it will expel through the overflow tube. You're not supposed to fill these radiators all the to cap like you do with modern - overflow bottle type radiators.

Remember water is generally not compressible, so when it expands, that extra volume has to go somewhere. Hence the need for a bit of an air gap at the top.

I believe Packard recommended filling the radiator to approx 1" below the sealing surface of cap.

Some have added coolant overflow tanks as efforts for correcting overheating but whether they actually do much more than add a comfort level is debatable. I don't care much for the light color plastic boxes that look out of place in older cars. If I were going to add one I would consider the approx 2" diameter by various length aluminum or stainless tanks that can mount vertically on the side of the radiator cradle. Painted black they are discreet yet serviceable.

While my '41 is not a Super Eight, it's a 120, it doesn't use "any". ie not enough that you'd notice, coolant since I had my radiator recored last year. Before the radiator was recored I was always adding to it to keep the level up, now that's a thing of the past. And to give some idea of use last month went on a 300 mile round trip and yesterday a 180 mike round trip. Both days the temp was 36c or more. The other thing is, the radiator cap is new so gives a good seal.

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With a good radiator and proper-fitting cap an overflow tank provides no benefit.