Why is my yz 125 getting coolant in the oil?
highest probability is the water pump seal is leaking. I know on the later models, they figured it out by putting a weep hole between the water pump impellor seal and the shaft oil seal but think that change occurred around 2000 or 2001. it’s also likely it could be either a head gasket blown, cracked head, cracked cylinder … but typically with these, it allows the coolant to leak into the cylinder where the coolant is mixed with the gasoline/air and pushed on out the exhaust … leaving you low on coolant but not usually in the oil … but could happen.
