Bongo Fury

Does anyone know why coolant is pushed out of my expansion tank when I rev the engine,
I have had a new head fitted, new water pump, and new radiator fitted, the thermostat is currently out of the housing, the expansion tank has been sniffed for combustion gasses and it's ok, could this be a blockage somewhere???

sounds like Air in the system to me with the symptoms you give.....

Agree with Mike - it needs bleeding properly (although without a thermostat, it should have bled easily)

Not shure the problem is air.
Try fitting a new cap to the header tank and make shure it is the correct one.

If you have ongoing issues with the coolant system you should
at least protect your cylinder head from overheating beyond
redemption by fitting a digital temperature gauge directly to
the cylinder head. The front 10 mm tapped hole on the passenger
side of the cylinder head is the best place to fit one and will
give you an instantaneous indication of the cylinder head temp.

I believe Kirsty and others have sourced a fairly cheap digital
thermocouple system from Ebay and can be easily fitted in minutes.
There is NO audible alarm; so it needs constant reading while
stationary or by a passenger when being driven. If there is air
in the cylinder head; the head temperature will rise rapidly and
a lot quicker than the temperature of the normal sensor which is
fitted lower down and may still be immersed in water.

A good healthy cooling system; when being driven lightly loaded
should indicate a cylinder head temperature of around 88 - 95 C.
This reflects the temperature change when the thermostat opens
and closes. When stationary - and the engine ticking over - the
temperature will rise to 100 - 105 C when the main cooling fans
should start; and stop the temperature rising any further. When
driven fairly hard; the cylinder head temperature may rise by a
further 10 degrees or so due to the exhaust gas temperature on
this side of the cylinder head.

If there is air in the cylinder head; then the head temperature
can - and will - rise enough to cause the cylinder block water
to boil and expand the normal coolant levels in the expansion
tank.

You should also be aware that ethylene glycol antifreeze will
prevent boiling in a pressurised cooling system up to around
130 degrees Celsius; whereas plain water will start to boil at
around 115 C depending on cap relief pressure. You may experience
a cylinder head temperature of up to 150 Celsius, but if you
allow it to go any further than this; you may cause serious
damage to the cylinder head which may be costly to rectify.

A quick and simple remedy for a working system would be to fit
a MASON gauge modifier or a Haydn TM2 which would give you
an audible warning of excess temperatures; but if you are having
serious coolant problems then the above will ensure that you cannot
overheat the cylinder head while you try and resolve the problems.

Thanks guys it seem a lot better now, it was either the extra bleeding I did or the damned good telling off I gave it !!!!!!