Another Cooling Q.

[Guest Stuart Ainslie]

I intend fitting an expansion tank to the standard single cored rad.

I have heard that you need a rad cap that can pass liquid both ways - at present I have the standard cap.

 

Whats the difference and what car was the cap fitted to??

 

Cheers....

 

Stuart.

[Guest TerryBarry]

Stuart,

The "standard" cap is a two way one.

There is normally a small metal disc in the centre of the lower sealing rubber - under pressure in the rad this is pushed up against the rubber forming a seal.

As the pressure rises above the preset 7 or 11 psig the centre of the cap rises overcoming the spring and water is allowed to exit the rad via the overflow tube. The spring maintains the seal but when the rad cools and the pressure in the rad falls below atmospheric this disc drops and allows air ( or water if there is a catch tank) to re-enter the rad.

Terry

[Guest Stuart Ainslie]

Thanks for the explanation Terry....

 

Sounds like the standard cap will be fine then.....

 

Stuart.