My 2004 YZ250F decided it didnt want to hold coolant anymore and started spewing out the weep hole, so this tells me the seal behind the water pump shaft has gone, now if I take the water pump cover and impeller off and dig the old seal out an I able to grease up the new seal and carefuly slide it over the shaft? Or do I NEED to remove the side casing etc? Only reason I ask is because I can't get a clutch cover gasket for a couple of weeks due to xmas etc and I'm riding the weekend, is anyone able to shed any light onto this for me?
Also what causes this seal to go? My bike got pretty hot on idle the last time I rode it, the header started glowing red so obviously shut it off, could the heat possibly of warped the seal?