Suspect BHG

[Sean]

Right Ran to billing didnt overheat but stopped just in time all the water in expansion bottle none in Rad after about an hours running bled the system got hot air thro to the matrix all ok set off again traveled another 1.5 hours no problem got to Billing same again let it cool all the water returned to the Rad out of the expansion bottle set off home sat in the queue to get out for 2 hours traveled 1.5 hours same again got her home took out the thermostat bioled it it opens just before the water boils so thats ok but it dont shut all the way should it ?? got no water in oil no exhaust gases in rad :banghead: i'm not acctually losing any water if i catch it before it over fills the expansion bottle it just pushes it out of the rad, :rant: . The system does pressurise

Any clues or Idea's please
or am i just hoping that it aint :crybaby: :crybaby: the dreaded BHG

[Bryank]

Right Ran to billing didnt overheat but stopped just in time all the water in expansion bottle none in Rad after about an hours running bled the system got hot air thro to the matrix all ok set off again traveled another 1.5 hours no problem got to Billing same again let it cool all the water returned to the Rad out of the expansion bottle set off home sat in the queue to get out for 2 hours traveled 1.5 hours same again got her home took out the thermostat bioled it it opens just before the water boils so thats ok but it dont shut all the way should it ?? got no water in oil no exhaust gases in rad :banghead: i'm not acctually losing any water if i catch it before it over fills the expansion bottle it just pushes it out of the rad, :rant: . The system does pressurise

Any clues or Idea's please
or am i just hoping that it aint :crybaby: :crybaby: the dreaded BHGThermostats tend to hang open when hot, so that's not a worry. suspect bhg to be honest, but given the 2 hours queue poss a minor one. try a retorque. not going to lose anything by trying,.. if it still does it after that, then gotta be a bhg. sure someone said there was a tester kit to check for combustion gases in the coolant..??

[Nick@TC]

Try a rad cap and new stat first.
We've got one in curently doing the same, but that is BHG.

You haven't done too bad mate, time for next round of mods :D
And get that bloody cat out, it won't be helping.

[Lofty]

I would replace the radiator cap and thermostat as a matter of course. Inspect the coolant hoses at the rear of the engine for signs of cracking or leakage. Flush the block, rad and heater matrix. Also check the hose between the radiator filler neck and the expansion bottle is not leaking or blocked. Might as well check the radiator for signs of leakage or damage too. Are you losing water because the expansion bottle is overflowing? When you got home how much water was in the system?

[nigel w]

sure someone said there was a tester kit to check for combustion gases in the coolant..??

Yeah, i've got one - i should've brought it to Billing! They'll set you back about £35 from a motorfactors. But unless its a bad BHG them the test wont be conclusive.

How quickly does the cooling system pressurise? If it reaches pressure before it reaches temperature then :crybaby:

[Bondango]

Sean i think its quite possibly air locking. Remember the heater Valve was staying down and we had to fix it up? is it still in the up position???

Rad cap could be a cure, and also a 5mm hole drilled in the stat should help bleed out any air..

Remember, not everything in life is a BHG :happy3:

[Lofty]

Sean i think its quite possibly air locking.
A definate possibility. I had a pinhole in the pipe that goes from the cylinder head to the heater valve. It didn't seem to loose any coolant but always sucked a small amount of air in as the engine cooled. Burping the system would get rid of it for a while but then the waterfall-dash would return. Replacing the heater components is a good investment as you would do this in the end anyway if you have a BHG.

[adi]

a normal test for combustion gasses may miss out on a BHG.. supposedly the best way is to get a test done 'under load' but very few garages can do this.. i know Chris wilson does it though..

[formal]

Sounds like a BHG to me. Had the same symptoms with mine. However it probably is worth checking all the water hoses etc. I would not recommend further tightening the head until you know what is up. As you are likely to mark the surface of the head by forcing the gasket sealing rings into the alloy head. This would require your head to be skimmed.

If you have a BHG then get it fixed - tightening the head will only do more damage.

[Sean]

Try a rad cap and new stat first.
We've got one in curently doing the same, but that is BHG.

It is a newish rad cap cos its done this to me before the cap seemed to cure it last time

You haven't done too bad mate, time for next round of mods :D
And get that bloody cat out, it won't be helping

I am planning MHG anyway but wanted to get the summer out of the way first

Lofty
yes the coolant loss is only because its pushed out of the expansion bottle got home after an hour all the water was still in the rad so its not a consistant thing I some times travel 1-2 hours before it does it

Marty
thats why i'm asking mate cos i just aint sure

[Lofty]

Did you fit a new thermostat or just put the old one back?

Another thing I can suggest is to pressurise each cylinder with compressed air at TDC and see if the water level changes in the rad. If it does then it is definately BHG. If they doesn't it is unlikely.

You could also pressurise the cooling system and see if that shows anything up. The cooling system should be able to hold a constant pressure if it's not leaking.

It may be a really margina leak either way though if it only does it sometimes.