Headgasket??

well the chemiweld's just going to get in the way of working out what the problem was. and It'll come back with a vengance probabley within say 20K Km.

repeat the test if you get the bubbles again put the cap back on and squeeze the cooling system hoses. if they are rock hard the head gasket is going.

Get the cap checked. V6 freelanders will boil with no cap on them. this is because when you put water under pressure the boiling point is raised.
This may be the case with the L series as the thermostat is fully opened at 96"c and fans start at 106"c also fans go to full speed at 112"c

Fill the Tank right to the top and run it. if you see bubbles constantly coming through the coolant it could be a blown head gasket.

I'm with camellandy Cant say I've seen a blown head gasket on a L series if it was a K1.8 or KV6 yes, even seen a few TD4s.

In your first post you said the coolant is bubbling out the top of the overflow bottle - is this with the lid on or off. My L series bubbles away quite happily but never out the top but has no issues. Also the L series will actually cool the engine quite well even without it being pressurised - accidentally left the cap off for a couple of weeks - never heated - didn't loose coolant. The other thing is the top of the overflow bottles craz and crack - doesn't seem to affect the system at all - new bottles will craz within a few weeks and as a result I have given up replacing mine.

If yours is bubbling out the filler then it can only be one of three things.

Air entering the system (check all connections etc), the system being pressurised (I agree that it is unlikely that the head gasket has gone - always a first though) (is the thermostat sticking allowing coolant next to the cylinders to get hot - when it opens steam exits the bottle - I do not think so), lastly is there a blockage in the coolant return pipe from the overflow bottle.

I agree with the others that it is unlikely that the headgasket is blown and the issue is most likely an overall cooling system issue - get it cleaned out and maybe a new thermostat.

If there is a leak or blown headgasket the chemiweld is most likely going ot hide that for a little while - I have a leaky heater matrix that I am too lazy to fix and chemiweld works well in fixing it for about a year and it will plug small head gasket issues for a little while.

Is the problem still there after you have used chemiweld?

Oh the obvious just occurred to me - have you replaced the overflow bottle cap - is it simply not holding pressure - doesn't seem to matter on mine though but may on yours.

Garry

Yeah, the cap is the first thing to check. Check is easy as follows. Squeeze the rubber hose (any hose) and notice no pressure in the system (easy to squeeze).
Start from cold, idle for 5-10 mins, squeeze that rubber hose again and notice the pressure build up (much harder to squeeze). If not the case - replace cap. New cap is not a warranty that it is a good cap.