header tank remove/delete questions

ukmercman Part of things Posts: 289	header tank remove/delete questions ukmercman @ukmercman
	Apr 11, 2012 18:26:23 GMT Select Post Deselect Post Link to Post Back to Top
	hi all. my header tank is currently here: i recently got an ally tank and positioned it in the far left corner, just in front of the fusebox - where the small black box is. the pipe that connects to it was lenghtened and runs through the firewall/bulkhead to the tanks new position. i now would like to move it to the far right corner - where the corner of the battery is just visible. my plan is to run the pipe from the existing spot, through the firewall/bulkhead, accross the bottom of the windscreen to the new position. so my question is: does moving the header tank further away from the orignal location (and lengthening the appropriate pipes to suit) have any impact on the cooling system? assuming the (new) position of the header tank is the highest point for bleeding - will it be business as usual? also - this: if i had one of these, could I fit it to the top hose and block the pipe currently running to the header tank, and not have a header tank all together? or would that not work? any help appreciated! thanks.
	Mercedes 2.5 16v www.mercedes-cosworth.co.uk

	Reply Quote

Gaztretropower Part of things vw for life,retropower Posts: 320	header tank remove/delete questions Gaztretropower @gaztretropower
	Apr 11, 2012 18:31:22 GMT Select Post Deselect Post Link to Post Back to Top
	As far as I no lengthening the pipe won't hurt,also have you looked into top fill rads?
	Well you will mess with these cars.... Mk4 golf gttdi highline. Mk2 golf 1.8T

	Reply Quote

hezekiel Europe Posts: 122	header tank remove/delete questions hezekiel @hezekiel
	Apr 13, 2012 6:10:19 GMT Select Post Deselect Post Link to Post Back to Top
	You certainly need a header tank. The empty volume is there for thermal expansion of the coolant. If you didn't have a tank, you would have to leave the system partially empty. This means the water pump would be whipping air into tiny bubbles suspended in the coolant. This has a detrimental effect on the cooling capacity of the system. The header tank is also a point in the system where the flow slows down and there is time for air bubbles to surface out of the coolant.
	Citroën DS 21 '66, Renault 16 TS '73, Scimitar GTE '74, Audi 80 '87, Merc 190E '88, Peugeot 205 GTI '88, BMW 735iL '89, Merc 230TE '89 , BMW 320i '92

	Reply Quote

cobblers Posted a lot Posts: 3,921	header tank remove/delete questions cobblers @cobblers
	Apr 13, 2012 8:43:06 GMT Select Post Deselect Post Link to Post Back to Top
	Yup, definitely don't get rid of it! Moving it shouldn't be a problem, although you'll have quite a long horizontal run on the bottom pipe, so filling the system from empty will be slow going. Might be worth popping the top hose off and filling the majority of it through there to save time. The volume of air in the header tank required is roughly related to the overall volume of coolant in the system. As hezekiel mentioned, the coolant expands when heated, and needs some headroom to expand, otherwise the pressure would build up too high - That's why you shouldn't fill the header tank right to the very brim - The system needs air space to expand into. If this volume of air is too small, the pressure will rise too much and you'll lose coolant out of the pressure cap. Top fill radiator systems usually have a secondary tank that they expel coolant into when it expands. When the coolant cools and contracts any excess is sucked back into the radiator. The tank doesn't necessarily need to be the highest point, it just has to be a point where water moves slowly. Being the highest point just makes filling easier.


	Reply Quote