Need help, oil mixing with coolant

Hello Everyone,

I'm new to Thumper Talk. Wish I had known about this site earlier. I have a problem with my 00' YZ426F. I was riding up in the mountains and noticed motor oil mixed with coolant coming from what I guess is the coolant vent hose. The bike continued to run until I got back to the truck, however it wont stay started now and just runs crappy. I've heard of a few things it could be...anyone have any ideas?

It sounds as thought your head gasket as blown, allowing the motor oil to mix with the coolant.Also check to see if theres coolant in the motor oil as well and maybe just to double check see if you can get a compression check done.

First check the simple things. Confirm that it is the coolant overflow hose and not the crankcase vent hose. It's fairly common for white creamy crap to blow out of the crank vent hose. Is your engine oil cloudy? Is your coolant in the rads cloudy?

It may also be a water pump seal gone bad which is also very common. There are 2 seals on the water pump shaft, one holds back oil, the other coolant. There is a weep hole under the pump that will usually drain whatever is leaking, but yours may be plugged.

This wouldn't explain the poor running, a head gasket would, but it could also be a seperate issue.

sure sounds like a head gasket to me. like they said check the levels and if your at all unsure do a oil change, then you know there will be good oil in there and you can work off that. coolant in the oil==white oil

another thing, let the bike cool off and take the rad cap off and look down in there to see if there is oil floating aound on top of the green. If thats the case it sure sounds like a head gask. make sure u flush the cooling system regardless when your done.

How many hours are on your bike, has it been raced?? any motor work done???

Well these things will get me started. I haven't raced the bike, but I am addicted to climbing hills, which keeps the RPM's up. I will change the oil and coolant and go from there. Hopefully not a head gasket!!! Thx

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