Coolant bottle location

[baltobernie]

I'm relocating the battery of my '73 Spider to the trunk. Can I place the radiator expansion tank next to the radiator? Must the bottle be the highest point of the chassis (as it is now on the firewall), or merely higher than the radiator overflow pipe?

[mbouse]

is that physics class i hear whispering in my ear? water seeks its own level, unless forced by pressure to go elsewhere.....or something like that.

if you have a properly functioning radiator cap, and a normally operating engine, the overflow bottle will see little if any use.

i believe proper installation will ask that you have the neck of the overflow bottle to be higher than the engine head.

[baltobernie]

But the heater core (or at least the in/out hoses) is higher than the water passages on the cylinder head. I think "seeking its own level" only applies to a vented system. I think you're right, Mike, about it being OK near the radiator - if memory serves, a 90's Thunderbird I owned had the radiator (and bottle) significantly lower than the top of the engine.

[So Cal Mark]

Mike, you've got that backwards; with a properly functioning system and cap the reservoir will see CONSTANT action. As the coolant heats and expands in the system it will be pushed into the reservoir and drawn back into the radiator as the system cools down. The reservoir can be placed anywhere, but about the same height as the radiator is optimum

[mbouse]

thanks for that clarification.