Leaking expansion tank

[daniel-1986]

is there a way to seal the screw top on the expansion tank as its leaks water/coolant. i bought a new cap (blue cap as told by a specialist) but its still leaking

[jmsheahan]

Does the cap have the black o ring seal in it?

[daniel-1986]

i dont know, i changed it straight away when i bought it from gsf

[Ben Lessani]

Is it leaking under pressure, or just leaking?

Could well be an airlock trying to find its way out.

[daniel-1986]

doin it under pressure, was doing it with the old cap before i had the headgasket changed. just been and checked the level aswell and there was a layer of ice in the water but not fully frozen. squeezed the pipes and there not solid

[Ben Lessani]

If your coolant has frozen, and your expansion tank is pressurising to the point where coolant is lost - it sounds like a cracked head, or poorly repaired HG.

I'd be inclined to do a sniff test on the coolant to see if you've got exhaust fumes in it.

[daniel-1986]

wat u mean by sniff test?

if the water hasnt funny frozen i shud be ok to start the car shudnt i

[daniel-1986]

wud it be worth draining the system and pouring warm water (obv not hot) donw there, i havnt started the car yet. its a 1.3 and from what ive read people with big block engines take the water pump belts off to warm the engine up without the pump turning but my water pump is part of the timing belt

[Ben Lessani]

If any of the coolant has frozen, I wouldn't even think of starting the engine until I visually inspected the water pump impeller and bearings, feel test of core plugs on the block, followed by a pressure test on the matrix, radiator and hoses.

A "sniff test" is to check there isn't exhaust fumes/oil in the coolant. If your head/block/HG has cracked/been damaged (however unlikely), then the compression stroke of the piston could well be pressurising the coolant.

[daniel-1986]

i bit the bullet and started the car without any problems, ran the car till the fan kicked in. Think i may hav to replace the anti freeze and water at some point. The coolant just smelt like coolant shud