I want to mount my header tank at the front of the car behind the rad but it means that the tank will be well below the top point of the system. Good or bad Idea? I have a phase 3 Zetec (Focus ST170 engine)

Thanks
Dave B

[Edited on 3/8/08 by Dave Bailey]

Not ideal, and it will be a pain bleeding the system. Why do you want it there? If you don't want to look at it go for the Raceline water rail and a cross flow thermostat housing - that way you can do away with the header tank and the TS housing will be the highest point.

Correct I don't want to see it plus I have a valve on the top of the rad I could use to bleed the system. Not sure I understand how using the Raceline water rail will remove the need for a header tank. Don't you need somewhere for expansion etc....

Dave B

That's the difference between a header tank and an expansion tank. A header is pressurised and part of the system - so on mine the header (VW) has a plastic pressure cap. It's quite unusual on mine because I also have the Raceline rail.

What I could do (and will at some stage) is put a pressure cap on top of the TS housing - which is on the exhasust side of the engine - and do away with the header altogether.

If I do that I'll need to keep a close eye on the water level, because I won't be able to check it in the header and any expansion will vent straight to atmosphere when hot. Not a problem if you check regularly anyway - which you should with a Zetec.

To get around this you can connect an expansion bottle to the valve on the rad cap. easiest thing is a drinks bottle. You put enough coolant to cover the hose in the bottom of the bottle and away you go - but you leave the bottle vented.

Good example here

http://www.tigersupercat.com/mods.htm