Radiator With Cap?

[brainbug007]

I know I'm probly daft and being a newbie here but I'm thinking about buying a rad off kit spares as the polo one I had cracked while I was trying to bolt it back on and now pisses out water :( I like the kit spare ones as they're new and the mounts are metal (I think) instead of plastic like the polo ones and it's a proper hole that a bolt with washer & nut could be used on instead of the bolt going into the rad. But I noticed that they sell two different ones, one without a cap http://www.kitspares.co.uk/shop/item.php?cat=4&product=4746&catsub=0 that's remote filled and pressure capped? Does the remote part of this description refer to the expansion bottle? The also do this one http://www.kitspares.co.uk/shop/item.php?cat=4&product=5104&catsub=0 which they describe as high efficiency for not much more but it has a radiator cap and a hose of some sort coming off it? What is the cap & hose for??

[deezee]

The 1st one (no cap) requires a header tank to fill / top up the system. The 2nd one (cap and hose) has a built in cap! and you can fill up your coolant system from that. The hose is an overflow in case the system is over filled / pressured. That might benefit an expansion bottle, but not sure if its an absolute requirement (it wasn't on my old MGB)

Edit: an expansion tank isn't the same as a header tank. The expansion tank takes any overflow from a system and isn't pressurised. A header tank is part of the system and is pressurised.

[brainbug007]

Ah gotcha, thought it might be something like that. I guess if I used the 2nd one it would have to be mounted quite high then or water would never really fill up the entire system?