2015 YZ450f Coolant Leaking out of Valve Cover Vent Tube



11 replies to this topic
  • cbriner916

Posted July 16, 2016 - 03:42 PM

#1

There is coolant coming out of what I am assuming is a oil vent tube on the right side of the motorcycle that comes off of the head.  Here is the interesting part though, it is not mixed with any oil, and upon draining my oil it was NOT milky.  We performed a cooling system pressure test and it held 25 psi no problem.  It would lose pressure as the bike was kicked over though. Could this be a strange head gasket problem? Or does anyone have any ideas? Thanks in advance



  • blurinthewoods

Posted July 16, 2016 - 03:59 PM

#2

Looking at the parts diagram for your bike seems to me like a valve cover gasket is probably bad.

Edited by blurinthewoods, July 16, 2016 - 04:00 PM.


  • grayracer513

Posted July 17, 2016 - 07:10 AM

#3

Uh, no.  The valve cover gasket has nothing to do with coolant.

 

Since your oil is not milky, I will assume this is yet another case of condensation in the crankcase vent tube, a very common occurrence in more humid environments.  Atmospheric water condenses inside the tube, then mixes with the oil residue it finds there and drips out looking like the dreaded "milk shake" kind of goop.  Nothing to worry about.



  • cbriner916

Posted July 17, 2016 - 08:26 AM

#4

Yes but if you read correctly I did not say valve cover gasket. And my radiator drains in about 60 seconds... So this is definitely a concern for obvious reasons

  • billygildark5007

Posted July 17, 2016 - 06:52 PM

#5

Is the bike smoking? Any pics of this drain tube? I don't know of any plausible way coolant would come from the valve cover bleeder without already being in the oil...

  • grayracer513

Posted July 18, 2016 - 06:23 AM

#6

Yes but if you read correctly I did not say valve cover gasket. And my radiator drains in about 60 seconds... So this is definitely a concern for obvious reasons

 

If you read the first response to your post, "blurinthewoods" did.  Where is the coolant going?  Does the oil level rise as the coolant disappears?



Visit the ThumperTalk Store for the lowest prices on motorcycle / ATV parts and accessories - Guaranteed
  • cowboyona426

Posted July 18, 2016 - 06:27 AM

#7

I'm guessing the tube you are talking about is the radiator overflow hose.  Small pinkish colored hose?



  • cbriner916

Posted July 18, 2016 - 03:27 PM

#8

Sorry Grayracer I missread, but the coolant is coming out of the black hose that comes off of the valve cover, not mixed with any oil, no change of oil level. I kid you not, it is straight coolant no oil.

but I am NOT talking about the radiator hose cowboyona426, Its a thicker black hose that is literally connected to the valve cover.

 

And billygildark, I would have said the same thing myself, but no smoking, It really makes no sense but somehow it is happening.



  • billygildark5007

Posted July 18, 2016 - 07:18 PM

#9

So if you remove the valve cover can you see coolant anywhere? It's gotta go somewhere as grayracer implied..... Either on the ground, in the oil, or out the back end...

  • grayracer513

Posted July 19, 2016 - 06:55 AM

#10

I knew what hose you meant right away.  Wonder how.

 

Is this "coolant" significantly green, or is it just water?

 

If you slowly remove the drain plug from the crankcase, does water/coolant come out first, or just oil?



  • blurinthewoods

Posted July 19, 2016 - 08:59 AM

#11

So you have removed the valve cover and inspected everything right.

  • billygildark5007

Posted July 19, 2016 - 08:39 PM

#12

Sorry if a bad idea but a pondering idea....
Do you live in a very cold temp winter and store the bike in freezing conditions without draining coolant/water?
Maybe a coolant jacket in head is cracked just in the right spot allowing coolant to pass threw when the motors running?
I'd imaging it'd still smoke horribly though...





Related Content

Forums
Photo

Michigan Motocross Tires by 288yz450


Dirt Bike   Dirt Bike Regional Discussion   North
  • 1 reply
Wiki
WR Camshaft Swap Info - last post by jamesm113

WR Camshaft Swap Info


Articles
  • 0 replies
Forums
Photo

Megabomb Fitment by 288yz450


Dirt Bike   Make / Model Specific   Yamaha   YZ 400/426/450
  • 1 reply
Forums
Photo

Is it worth it? (Cam and High compression piston) by macgi77


Dirt Bike   Make / Model Specific   Honda   CRF 150/230 F/L
  • Hot  36 replies
Forums
Photo

2016 YZ450 by CaptainKnobby


Dirt Bike   Dirt Bike Technical Forums   Suspension
  • Hot  59 replies
 
x

Join Our Community!

Even if you don't want to post, registered members get access to tools that make finding & following the good stuff easier.

If you enjoyed reading about "" here in the ThumperTalk archive, you'll LOVE our community. Come join ThumperTalk today!

The views and opinions expressed on this page are strictly those of the author, and have not been reviewed or approved by ThumperTalk.