coolant coming out of my motor!!!! wat!!!

2 replies to this topic
  • 426 boy

Posted September 18, 2007 - 11:32 PM


Hay guys i have the weirdest question for you.

I have a 2002 YZ426F

i was riding the other day for about 3 hours and then put my bike in the shed:worthy:

Theeeeeeen when i got it out the next day i checked the coolant level and:crazy:it was down bout 200ml

so i checked all the hoses and all was tight except the alluminium one that comes out of the head it was weeping slightly. I think the seal wasn't quite seated properly. So i repaired it and it was all good.

so i started it up and i saw:eek: coolant spitting out of the black motor oil breather hose??????????????

OH NO!!!!!!!!!!!!!!!

I am 99.99999% sure its coolant coming out, but only little droplets. I took the cam cover off and theres no sign of water/coolant.



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  • grayracer513

Posted September 19, 2007 - 05:32 AM


What's weird about it?

First, assuming you fixed all the real leaks, the bike will still "loose" coolant as long as you fill it to the top when cold. Coolant expands when heated, and it has to go somewhere, so the expanded coolant pushes out the overflow as you ride until there's enough room for it in the radiator. Once it cools down, you'll find the level at about the top of the tubes, and it should stay there from ride to ride without adding any.

So, if that holds true, and your oil has not taken on a distinct milky look, the few drops of water you see at the breather are most likely condensation from the air in the tropical island paradise where you live.

  • USED YZ426F

Posted September 19, 2007 - 06:37 AM


I agree with Grayracer. If your oil does not have the milky look, then water/coolant is not getting in to the engine.

I work for the US Navy and we add a non-reactive dye in all of our cooling systems to help us locate real leaks and differentiate between cooling leaks and condensation. If you are still concerned that you have coolant leaking from the oil breather tube, you can add a little dye (check your local auto/marine parts dealer to see if they have any in stock) to your coolant and see if it comes out of the breather (I seriously doubt it will). The dye also makes it very easy to track down any small leaks in the cooling system. I have used this technique to track down coolant leaks on a boat, snowmobile, quad and a few cars.

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