hoping my bus will once again be roadbound very soon, have just been sorting out the finer details. i am setting up 2 small rads under the car, very similar to Helbus or Customoffroads setups. one of my rads has a small breather/overflow outlet in the rad and i was thinking of using this to keep the radiators topped up, running the hose up and into a container inside the car. will this work fine?
otherwise i just scored a welded water tank from a V12 Jag which has smallish hoses coming from it and i am thinking about tapping some connections into the thermostat cover where the upper rad hose connects and attaching the tank into there. would that be a better option? would it be secure enough to tap some fittings in (i think it is aluminium or alloy the bit that i would be tapping into) or would i have to get them welded/brazed on?

[ Edited on 11-7-2006 by baybuscamperkid ]

I would say ideally you would want hoses with at least 5/8" internal diameter like heater hoses. The header tank in most cars has only one hose to it with a size like that, and then an overflow tank as well. If the tank you have is aluminium, then it has to be TIG welded to attach or close off holes. Cheap header tanks can be found in plastic from Pick Pay n Go in Ringwood off all sorts of cars, like 90's Falcons.

ok, just re-thinking a little, i think i have come up with the right solution. use the breather on the radiator, hook that up to the lower fitting on the tank that i have and mount the tank so that its middle is inline with the top of the engine, then fit a small line to the thermostat housing on the engine to act as a breather to expel any air from the top of the engine.
how does that sound?

The breather on the radiator is for overflow, not header tank work.

A header tank is designed specifically to be the highest fill point on the system, allow air bubbles to rise to it, and be permenantly connected and pressurised with the radiator, that is why they have the actual radiator cap on them.

An overflow is what is connected to the small pipe next to the radiator cap. It is only used for expansion of fluid when the radiator is hot, and will allow return of the fluid as the radiator cools.

Hope that helps, and sorry if am misunderstanding what you have, as I have no pics.

no thats fine, helps alot thanks peter, was hoping to use a more unconventional method (had thought the pressure from the header tank attached to the radiator might be enough to push the air bubbles out through a breather at the highest point - the thermostat housing where the top rad hose attaches)
cheers

I browsed through our (dutch) classifieds site, and there are quite a bit of people trying to sell filler tanks (which I think will be difficult to sell..).
I haven't seen any manufacturer that used a flow through filler tank.

What would be the reason they aren't used? I think/hope it's because of the location car manufactures want for their tanks. Normally the tank is placed on the side of the engine compartment while the coolant hoses are somewhere in the front.

It will be difficult to find a car with a flow-through tank, because almost all of the engine compartments have the same setup. Maybe if a car has a rear or mid-engine setup, it will make sense to use a flow through tank.
So....T3 bus? Toyota MR2? Old rear engined Skoda's ? Busses/vans that use an under-car radiator?

[ Edited on 17/7/2006 by gerrelt ]

The only thing I would do differently is to have the outlet of the header tank at the bottom also. Certainly no problems with filling it up. I just filled it once, ran hot until thermostat opened, then topped up. There was no problems filling and refilling to get air bubbles out.

Not really that expensive to get made up in aluminium.