Coolant bleeding problem

8th July 2014, 14:49

Done this a million times without issue. Today however...

After rebuilding the engine - head gasket change - i ran the car (16v) after filling it up and bleeding with the two bleed points, and stuck in a 2litre bottle to the rad neck with some coolant in. First time I hadnt wedged the bottle in well enough, so it fell out lol. Ran it the second time, got loads of bubbles out, was about the point where the fan was about to kick in (mark above the medium level on the temp gauge), but then the coolant started rising up the bottle about a cm a second. Kept rising, rising, rising, then pished out the top of the bottle all over the engine.

Wtf is this about? Never had this nonsense before, normally Ill sit and watch the car while its bleeding and have something to eat, never a problem before.

Guessing the thermostats ok as the top hose is roasting. Im at a loss though.

8th July 2014, 14:54

Is the coolant hose near the engine top mount hot?

8th July 2014, 14:55

For the sake of a bucket and popping the lower hose off, you may as well start again.

Also there's 3 bleed points, the radiator screw, the allen bolt on the thermostat housing, and the nipple on the matrix to block feed pipe.

Also don't listen to me, mines bled up and runs a treat but my heaters are cold so I need to do it again tomorrow.

8th July 2014, 14:55

The one to the left of the inlet mani? Yeah thats hot too.

8th July 2014, 15:02

How sure are you of the rebuild?

Do you have a coolant tester to test for gasses/fuel?

8th July 2014, 15:19

Ive only ever done it by the inlet one and rad tbh.

8th July 2014, 15:32

Quote:

Originally Posted by Prickle

Ive only ever done it by the inlet one and rad tbh.

You've never used the one at the back of the block?!

Or do you mean you've used that and not the thermostat one?

8th July 2014, 15:36

No, i said i have lol. you can get away with just using one. It just takes longer obv

Heaters blow hot and good like.

Sorry to be of no help Gab.

8th July 2014, 15:39

Quote:

Originally Posted by chompy

How sure are you of the rebuild?

Now this has happened, not very. Though Ive done more than I can remember before, and this time I was the most meticulous and thorough Ive ever been.

Tested the comp figures there, so still warm and w.o.t., all cylinders running at near enough the exact same values, maybe 0.25bar difference across them absolute max. Though I can only think the cyls are pressurising the coolant like you said.

Rage.

8th July 2014, 15:39

Quote:

Originally Posted by Prickle

Sorry to be of no help Gab.

FFS man Prickle, you're fucking useless you like. Sheesh..

just kidding lolzzzz

8th July 2014, 15:40

Quote:

Originally Posted by Gabbastard

Now this has happened, not very. Though Ive done more than I can remember before, and this time I was the most meticulous and thorough Ive ever been.

Tested the comp figures there, so still warm and w.o.t., all cylinders running at near enough the exact same values, maybe 0.25bar difference across them absolute max. Though I can only think the cyls are pressurising the coolant like you said.

Rage.

Much like the old IT adage, I'm thinking the solution here is going to be to take the head off, then put it back on again.

8th July 2014, 15:43

Quote:

Originally Posted by D4MJT

FFS man Prickle, you're fucking useless you like. Sheesh..

just kidding lolzzzz

Got to keep the +1s man.

8th July 2014, 15:44

Quote:

Originally Posted by Gabbastard

Now this has happened, not very. Though Ive done more than I can remember before, and this time I was the most meticulous and thorough Ive ever been.

Tested the comp figures there, so still warm and w.o.t., all cylinders running at near enough the exact same values, maybe 0.25bar difference across them absolute max. Though I can only think the cyls are pressurising the coolant like you said.

Rage.

I suppose a possible easy way to check would be to unplug the coilpack, crank it for a few mins then drain and smell the coolant. It'll reek of petrol if they're leaking.

But judging by the constant compression i'd say it's unlikely. Try bleeding it without the thermostat in (that way you can do it from cold)

8th July 2014, 15:50

whats it do if you shut it off (before it bubbles over) and let it cool naturally?
Mine was a pain like this as I've got no bleed valve up by the inlet

8th July 2014, 17:14

Christing fuck...

Filled it up again, bled from the points, ran it and its totally fine now. Bubbles appeared til just before the fan ran, bubbles stopped, fan kicked in, no boiling over.

Took it a run, heaters are toasty hot, coolant temp sitting nice and steady.

Fuck knows man. Seems - fingers crossed - to have sorted itself.

Cheers for the input guys, will update the thread if anything goes awry.

8th July 2014, 19:24

Score!