Please help coolant issue

[flumpy7]

Hi guys please help put my mind at ease. I recently drained and changed the coolant on my gpz500. If i remove the radiator cap with the engine running (when hot),the coolant starts spilling out. If i remove the cap and idle the engine from cold, as it gets hotter the cooant level gets higher until it spills out. When it stop the engine the level drops again. Is this normal? My engine has not overheated yet...the temp level on the gauge is always below the red level. (In busy traffic for long periods it does occasionally get to just under the red but never actually goes into red). The level in the reserve bottle is not getting lower or higher and does not appear to bubble, although when i remove the radiator cap and rev the engine the coolant does bubble then. My bike has no other symptoms...no smoke no suspicious noises or smells and there are no signs of any coolant in the engine oil or vice versa. Is it possible i have head gasket issues? Thanks in advance!

[Kickstart]

Hi

Normal. Coolant has a high boiling point when under pressure. With the cap off there is no pressure so it boils at a lower temperature.

All the best

Keith
____________________
Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing

[flumpy7]

Thanks for that, really helpful. I let the engine cool down and then added more coolant direct to the radiator. I filled it up right to the top...is this OK? Just checked the manual and it says i should have filled via the reservoir only. Is this a prob? I just thought as it overflowed out of the radiator i'll just put it back in where it came out. The manuals a bit unhelpful as it says when you change the coolant you should full the radiator up to the correct level....but there are no markings so i dont know if i have filled it too high?

[Kickstart]

Hi

You are probably fine on the level then. What happens is that if the pressure in the radiator gets too high then the cap releases the pressure and allows it into the header tank.

All the best

Keith
____________________
Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing