18-06-2015, 09:43 PM
Ideally you don't want to be using an overflow tank - this is because the top of the radiator is not the top of the system unlike MOST cars - remember that the radiators with the tank on the side are not just attached to the radiator, they're an expansion tank that happens to be connected to the radiator. If you get air in the top of the radiator - which can happen with an overflow tank double spring rad cap setup, when you turn off the engine, the air will go backwards into the thermostat housing, possibly causing an airlock, this also means that the bleed line that goes to the top of the radiator is defunct - because it's likely to be filled with air - this is why the stock radiators have a bleed on top of the radiator, to ensure there is no air in the top, because you'll air lock the cylinder head if you do.
Of course, if XUDs had a "normal" cooling system, they'd be fine, but unfortunately, they have an odd design which means that they've very sensitive to air'ing up and can't get the air out easily. Placing an overflow style radiator which has a radiator cap on top in the system means you increase the chance of this happening greatly, hence I said, shim the radiator cap on the radiator you have to stop any air getting in due to it's overflowing double spring design. Then use a normal expansion tank tee'd into the lower radiator hose, you can then place this wherever you want in the engine bay, higher the better, since this will make it much easier to bleed the system as you can get the water in the expansion tank to be the highest point.
As always, my opinion - people aren't bound to have to use my opinions of course, but if asked, I'll always give them.
Of course, if XUDs had a "normal" cooling system, they'd be fine, but unfortunately, they have an odd design which means that they've very sensitive to air'ing up and can't get the air out easily. Placing an overflow style radiator which has a radiator cap on top in the system means you increase the chance of this happening greatly, hence I said, shim the radiator cap on the radiator you have to stop any air getting in due to it's overflowing double spring design. Then use a normal expansion tank tee'd into the lower radiator hose, you can then place this wherever you want in the engine bay, higher the better, since this will make it much easier to bleed the system as you can get the water in the expansion tank to be the highest point.
As always, my opinion - people aren't bound to have to use my opinions of course, but if asked, I'll always give them.