Fitting a modern expansion tank

[had17462]

Hi all I am fitting a vw  header tank which has  two exit pipes the lower one  will go to the thermostat housing which will have a pipe exiting it for the said pipe, then the radiator overflow pipe will go to the top of the header tank, anyone else done a closed system please advise.

regards

Nick

[Hamish]

Hi Nick

i know mine is a 3a but it’s the same principle 

i fitted this tank the expansion take off pipe is the “old” overflow fitting under the rad cap. This rad cap is replaced with a blanking cap. Ie no pressures spring.

the pressure spring is fitted to the expansion tank. 

This way the coolant system can be a little fuller in the long rad neck these cars have and the heat expanded fluid can flow too and from the expansion tank. The overflow is still there under the cap of the expansion tank. Not that is has happened since fitting.

 

 

 

Edited June 24, 2019 by Hamish
Double pics

[Motorsport Mickey]

Hi Hamish,

The end of the pipe feeding into the expansion tank needs to reach down to the bottom inside the expansion tank otherwise there will be no vacuum and subsequent sucking back of displaced fluid. That tank looks like a small header tank which only has a feed in unless there is another pipe feed from the tank which rejoins your system somewhere.

Mick Richards

[Hamish]

Hi mick

yes the tank has an internal rigid metal pipe that goes to the bottom of the tank. So as the pressure decreases / liquid cools is gets drawn back into the rad.