Coolant overflowing from cap

[SS Tim]

Originally Posted by Stocker

I understand not filling to the top if you don't have a coolant recovery system.... but did any of these rigs come from the factory with one? The factory sealed systems I've seen have the radiator completely filled. My '72 has a recovery tank and the radiator is filled to the top.

Agree as to needing the correct cap, as posted above.

Everthing I have seen has been a loss system from the factory. The closed example was used for people who have modified their systems. Problem is not everyone understands the difference or has not been exposed to anything but a full recovery system.

A recovery system is plumbed in such a way that the fluid can vacuum return typically a hose extending to the bottom and maintains a minimum fluid level in the recovery tank as well. A catch can only catches it and does not have a return path and may easily be empty. If you have modified the cooling system in such a way as the fluid can return (tank and recovery cap) then yes fill it to the top and enjoy a little more heat rejection. But if there is not a path then use the factory level as intended to reduce the venting from the closed system to the ground or catch can.