Cooling system issue

My bike has, during my last 2 rides, been leaking coolant. It appears to be leaking from around the radiator cap and i was pretty sure that it was just an old cap and was about to order a new one. BUT! As i removed the cap after work today with the bike STONE COLD (not riden since sunday) i found that it was under pressure and proceeded to leak about a litre or so of coolant. I've never experienced this before and found it to be a little odd. Has anyone else experienced this or know a possible cause before i run off to the mechanic? Oil is not murky at all either......

My old Datsun 1600 did that when it had a cracked cylinder head... the oil looked OK then too.

yeah i think i might have a head gasket issue

I remember my Dad telling me he used to pour porridge into the radiator of his Bren gun carrier during the war to fix head gasket leaks.

Funnily enough, I never let him work on any of my vehicles after that...

get a TK test done on it.. [Detects CO in the cooling system e blown head gasket]

Make sure you have no oil affected / stuffed coolant hoses that could be ballooning.


nb.... ground pepper works to get you home and doesn't stuff the rest of the cooling system in the process..... don't know about porridge!?

nb.... ground pepper works

Do you get squid with that ?

My initial reaction was cracked head/head gasket, but wouldn't the pressure leak back down from the coolant to the motor as it cools down?

You sure it was a litre? That's an awful lot of coolant coming out of a really small cooling system.

I'd be checking hoses and radiator cap before assuming the worst. As IoN said, get the TK test done if you want peace of mind. Combustion pressure leaking into the cooling system will more commonly push coolant out the overflow rather than the cap. And as Mike said, it would also usually be accompanied by a LACK of liquid in the system when cold, not too much.

You've probably got a dud radiator cap and some badly softened hoses.

nb.... ground pepper works

Do you get squid with that ?

Depends on wether you leave your fav' Joe Rocket gear behind or not I spose????

Dropped the bike into RB Racing today and they're going to pressure test it for me just to make sure it's not the head gasket. Quite possibly just the radiator cap tho. Thought it best to get it looked at rather than just throw a new cap on and have it shit itself out the back of woop woop somewhere.