I have a new radiator on the way, so will be changing out the big old Ford one I have at the moment. It currently has a filler hole in the Rad and the header tank has one small pipe going to the top of the rad. The Rad has a Cap and the header has a pressure cap. So i undertand if the pressure grew then the pressure cap would vent the presure from the header... Bear with me


So I have looked at the Golf MK3 header tank which will allow me to fill with water as the bottom pipe is a bigger bore, the upper pipe I guess goes to the top of the new Rad. However, it looks like the cap on the Golf Header is simply a screw on type (???) - So if this is the case how would any excess pressure in the system be vented, becos this is sealed now.... or is that the point. Have I missed something ??

The screw on cap is still a presure cap that vents at 1bar via a valve in the cap.

adrian

As Adrian said, the cap still vents, into a built in channel in the bottle which exits via 2 square holes just above the mounting flange.

ATB
Stott

Ahh, that makes more sense - Cheers fellas