'99 CBR600 F4 Overheating - Oil in coolant
1999 F4, original owner, last model year with carbs, have done extensive upgrades to it over the years, it's a track bike and daily driver. Heads are milled .020", 1.7 jet kit, full micron system, racetech suspension... yada yada... I do all my own work, but this has me stumped....
Lately I've had an issue with overheating. +240 degrees at idle. Moving tends to cool it down enough, but you can feel heat dumping off the fairings as you move.
I dumped the coolant and it appears that there is a sludgy oil residue mixed in with it. So I'm thinking head gasket. A leakdown test showed that 5% on #1, and 3% on the rest. No bubbling in the radiator while testing. Just air noise in the crank/oil fill spout (normal).
Ran bike with a cooling system pressure gauge on the radiator. Pressure slowly went up to 16 psi where it's supposed to be... then continued to rise as the bike warmed up, up to 28 psi then I shut it down for fear of damage to the cooling system internals.
So I think it 'could' be a headgasket as something is pressurizing the cooling system. Pulled the heads, no obvious signs of a break thru in the gasket or burns where combustion blew by... Gasket looks normal for all intensive purposes.
I'm thinking now that the oil inter cooler has a break thru leak that is allowing high pressure oil into the cooling system.
Is this a problem that anyone has seen before? Before I go and buy another cooler? Any testing ideas on the old one?
FYI, I don't see any coolant in the oil after draining it, no white milkiness.....