Re: Radiator overflow tank

Posted by BigKev On 2016/2/14 22:20:22

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.