Water pumping out of header tank !

[HeskinBongo]

Recently had an overheating moment

Refilled and bled the system, took about 40 mins

Let it cool, topped up and ran again, instantly the header overflow pumps water out a steady stream for 3 mins, then splutters a bit and then stops, engine temp normal then soon starts rising. turned it off !

When i take the header cap off (after allowing to cool) the system is pressurised so i can assume header cap is OK as it holds the system pressure YES ?

Is it not bled correctly for this to occur ?

Engine runs fine, no water in oil etc
Should I check the thermostat ?

Thanks for any comments

[lpgimports]

Need to bleed it again in the first instance, if it pressurising itself then it is not a good sign, Bongo's dont tend to mix oil and water they tend to blow headgaskets between combustion and water so hence pressurised water system. Additional likelyhood of cracking in head if your unlucky as well.

It needs a block test, and a pressure test to see if combustion gases are present in the water, if so then headgasket at the minimum.

Paul

[alan]

let hope not but mine did this and ened up having a new head fiited#-o

[321Away]

It might just be an air lock, try re-bleeding the system or letting it overflow and cool down and refill sometimes that can clear an airlock, are the heaters blowing cold air?

Julian

[Darkstar]

not wanting to put the cat among the pigeons,
but when the coolant reaches optimum temp would'nt a pressure build up be expected due to the coolant expanding, now i may be wrong but would not some of the pressure be release through the pressure cap, thus causing a vacuum when it then cools down, and this is what is heard when removing the header cap?.

like i say its only a theory,

[bigdaddycain]

Hi Heskinbongo... It doesn't sound good... I'm not wanting to alarm you but that's classic bongo symptoms of an impending head/gasket failiure... Don't let anybody tell you that drilling the stat out keeps the coolant from spewing out! It will stop it.. but it's masking another more serious impending problem. I'd get it pressure/sniffer tested sooner rather than later...

Best of luck.

[mikexgough]

any updates on this?..... my 1st thinking is there is air in there ...... and 1st question is... Did you bleed it cold, i.e. removing as much air as possible during refill? before starting the engine.....
This is always a good start as it leaves little trapped air to be bled when the engine is hot and makes bleeding simpler....

[HeskinBongo]

The conclusion to this post

thanks to Northern Bongolow, several pm messages and a visit today from him, and having gone through the cooling system in a methodical manner, using a pressure tester etc
This is what was found :-

a, radiator cap leaking at 1bar
b, thermostat (non std) internal sealing rubber distorted
c, pump to rad steel link pipe, has small leak from rust blister (could burst at any moment!)
d, head cracked, now confirmed by the amount of air bubbles filling the bleed funnel, which are generated at a relentless rate so must be from the combustion side
oh yes e, ran out of coffee

So i'm debating taking the head off myself !

Anyone got a sound head or engine ?

[mister munkey]

Bummer.

At least you're in good hands, apart from runing out of coffee, that place is usually pretty good.


Bongobits are good for heads but they seem to be a bit slow on internet orders lately. Try a phone call to the shop 01752 250777. They can do next day delivery in most cases.

[Northern Bongolow]

you know me better than that chris, he ran out of coffee .
glad to have helped,but sad to give the conclusion that you already thought you had.
hope your soon mobile again.
good luck.

[mikeonb4c]

The conclusion to this post

thanks to Northern Bongolow, several pm messages and a visit today from him, and having gone through the cooling system in a methodical manner, using a pressure tester etc
This is what was found :-

a, radiator cap leaking at 1bar
b, thermostat (non std) internal sealing rubber distorted
c, pump to rad steel link pipe, has small leak from rust blister (could burst at any moment!)
d, head cracked, now confirmed by the amount of air bubbles filling the bleed funnel, which are generated at a relentless rate so must be from the combustion side
oh yes e, ran out of coffee

So i'm debating taking the head off myself !

Anyone got a sound head or engine ?

Does it have to be the head, or could it just be the gasket? You must obviously get the head pressure tested, but perhaps there is a slim chance it will pass as OK? Need to observe the rules for successful rebuild (new stretch bolts, flat the block properly, possibly use suitable gasket sealant as I think Simon Jones did with good results, although you are not supposed to have to)