Grey engine oil - solved!


5 replies to this topic
  • Jon E

Posted March 28, 2014 - 01:08 PM

#1

This article may help if your oil turn out to be GREY! And first, excause my bad english. The solution is related to this post: http://www.thumperta...o-coolant-leak/

 

I bought my 2009 Yamaha wr450f last year. It had only 4200km on speedometer, and the bike looked like new. It is a full power version. I am mostly using the bike to commute to work. No hard driving at all, short trips.

 

When i bought the bike, the engine oil was black. Every thing looked allright. After commuting to work for a month or so, i checked the oil again and it turned out to be really GREY!!!

 

I asked forums on the internet for help, and most of them respond that there is water in oil (witch turned out to be right, sort of..!). Their suggestions are:

 

  • Blown headgasket most likely, coolant leaking into the engine
  • Water pump seal is leaking into the engine (Note: The water pump cannot leak coolant into the engine oil.  The coolant seal is separated from the oil seal on the shaft by an air gap that allows coolant to escape.)

Here is the elemination method i used (i had many oilchanges with GREY oil before i finally got to think of the nr. 3, witch turned out to be the solution):

 

  1. Replaced head gasket, piston and rings. Still REALLY GREY oil after only a few days commuting to work!
  2. Mounted a transparent tube on the radiator and overfilled it with coolant. No coolant at all leakes into the bike.
  3. Rerouted the breather hose from the electric starter out into free air. Oil went NORMAL again!

In retrospect, the cause of the grey oil problem on my bike is that the "enclosed Y" breather hose system (see images below) has transfered moisture from the head direktly into the engine again trought the starter motors breather hose. Because i almost NEVER drive the engine really hot! The engine never get warm enouht to evoporate on my short 10 minutes trips. My breather hose was producing condensation (i could see condensated water dripping when i dismantled the hose) every time the bike stopped, and poured it back into the engine... It was a big surprise that it would produce that much condensation.

 

Now, i take good 50km ride every now and then, and the problem has dissapeared entirely. All that f****cking work for nothing... Lesson learned :-)!

Attached Thumbnails

  • grey.jpg
  • motor.jpg
  • motor-copy.jpg

Edited by Jon E, March 29, 2014 - 12:46 AM.


  • grayracer513

Posted March 28, 2014 - 02:26 PM

#2

It will probably surprise you to know that your theory about the breather tube simply moving air back and forth between the cam box and the crankcase is inoperative for the simple reason that there is only one internal air volume in the engine.  The top end camshaft area is connected by the vastly larger cam chain tunnel, and the air pressure in both places rises and falls simultaneously in any case.  As the piston goes down in the bore, air is push out through BOTH hoses to the Y and outward.

 

Routing to the atmosphere rather than the air boot doesn't really do anything different, either.  Both are a connection to an open air space, and accomplish the same thing. 

 

If you left the Y disconnected as shown in your diagram, you create a path for unfiltered outside air to enter at the Y and be drawn in under your air filter, bypassing it.



  • mrgem

Posted March 28, 2014 - 04:53 PM

#3

This article may help if your oil turn out to be GREY! And first, excause my bad english. The solution is related to this post: http://www.thumperta...o-coolant-leak/

 

I bought my 2009 Yamaha wr450f last year. It had only 4200km on speedometer, and the bike looked like new. It is a full power version. I am mostly using the bike to commute to work. No hard driving at all, short trips.

 

When i bought the bike, the engine oil was black. Every thing looked allright. After commuting to work for a month or so, i checked the oil again and it turned out to be really GREY!!!

 

I asked forums on the internet for help, and most of them respond that there is water in oil (witch turned out to be right, sort of..!). Their suggestions are:

 

  • Blown headgasket most likely, coolant leaking into the engine
  • Water pump seal is leaking into the engine (Note: The water pump cannot leak coolant into the engine oil.  The coolant seal is separated from the oil seal on the shaft by an air gap that allows coolant to escape.)

Here is the elemination method i used (i had many oilchanges with GREY oil before i finally got to think of the nr. 3, witch turned out to be the solution):

 

  1. Replaced head gasket, piston and rings. Still REALLY GREY oil after only a few days commuting to work!
  2. Mounted a transparent tube on the radiator and overfilled it with coolant. No coolant at all leakes into the bike.
  3. Rerouted the breather hose from the electric starter out into free air. Oil went NORMAL again!

In retrospect, the cause of the grey oil problem on my bike is that the "enclosed Y" breather hose system (see images below) has transfered moisture from the head direktly into the engine again trought the starter motors breather hose. Because i almost NEVER drive the engine really hot! The engine never get warm enouht to evoporate on my short 10 minutes trips. My breather hose was producing condensation (i could see condensated water dripping when i dismantled the hose) every time the bike stopped, and poured it back into the engine... It was a big surprise that it would produce that much condensation. Lessen learned.

 

Now, i take good 50km ride every now and then, and the problem has dissapeared entirely. All f****cking work for nothing... Lesson learned :-)!

Great post. Very useful information!



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  • Jon E

Posted March 29, 2014 - 12:32 AM

#4

grayracer513; "Routing to the atmosphere rather than the air boot doesn't really do anything different, either.  Both are a connection to an open air space, and accomplish the same thing."

 

That is also my understanding. But when i disconnected the breather hose from the starter engine, it was every time dripping condensated water (by the gravity of the long hose) into the engine. It is better not to have that water inside the engine... I might put a filter on the breather hose end, or simply put the breather hose to the start motor on top of the the "Y" - not bottom. I might also connect the breather hose back to its origin, but my point in the article is the bike needs to get warm. And now, from time to time i ride the engine really hot and the grey oil problem goes away!!! :-)


Edited by Jon E, March 29, 2014 - 12:43 AM.


  • GuyGraham

Posted March 29, 2014 - 01:59 AM

#5

Jon E

You have found the cause of your problem - 'the bike needs to get warm'

 

It is designed not to overheat when used as intended ie slow speed in the woods

Using it on the road, over cools the engine (no thermostat to control the water temp, and 2 big radiaotrs at full flow)) and so the condensation doesn't evaporate from inside the engine, but just ends up mixing with the oil

 

I had problems when I first had mine, and I was just blasting around the country lanes on it, getting used to it etc - I had a horrible white gunge collecting the pipe from the starter motor housing.

Then, when I started using off road, with lots of first and second gear ie not moving through the air that fast, and hence being cooled less, the problem went away completely

 

You could try blocking off one of your radiators with a suitable piece of cardboard

This will make the engine run hotter and will help



  • grayracer513

Posted March 29, 2014 - 04:19 PM

#6

Condensation may accumulate in the oil if it is not raised to normal temperature ranges (200-250 ℉) and kept at that temperature for 15 minutes or more.  That simple.






 
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