Oil found in coolant??

[brenduro999]

Hi lads, i was just going over the bike as im just back from a 3 hour longcross event and i opened the rad and there seems to be oil mixed in with the coolant?? i assume its a seal in the water pump maybe? other people have said it could be the head gasket but if it was that then id assume that would pressurize the system and blow out all the coolant!

Has this ever happened to anybody else?

 

[gasgasman]

Water pump seal gone bad.
I had to do mine a few months ago. Be sure to change the water pump shaft bearing too.

The head gasket has no physical connection to the transmission. So it can't be that.

 

[husley]

Me too

My 2010 did the same at about 50hrs.

The screw that holds the impeller in place was loose. Subsequently there was not enough pressure on the seal (behind the impeller) and oil could flow from the tranny into the cooling system.

 

[brenduro999]

I Drained the coolant and it was clean? I then took the water pump cover off and I couldn't find any oil around the inside of the water pump! And there's no play on the shaft either! I'm stumped??

 

[Jakobi]

Might just be a smidge of assembly grease thats made its way to the top of the system. How much are you talking about?

 

[gasgasman]

I Drained the coolant and it was clean?

When the coolant cools off, it creates a vacuum in the cooling sytem. This vacuum draws oil into the cooling sytem through the bad water pump seal.

The residual oil is probably trapped in the radiator.

 

[brenduro999]

There wasn't massive amounts of oil in the system, only a little when I first opened the rad! Just thinking now, is there a breather pipe on the gear box? Can't say that I've noticed one myself but if there was what's the chances of that blocked up and forcing a little oil through the a water pump seal? I'll take a look first thing in the morning if there is a breather pipe!

 

[Jakobi]

The breather is the tube that runs off the top of the RHS powervalve cover.

 

[GMP]

Also, the pump seal is different than most bikes, it's a spring loaded high speed ceramic/graphite seal. It seals harder the higher the coolant pressure, so if you have a vacuum in the cooling system side like Girard stated, your working opposite the design direction of the seal. Usually no problem, but if the seal is old that would be a likely leakage point. Leave the rad cap off as the bike cools and see if it still happens.


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[(F5)]

put a thin shim behind my impeller to preload the seal a little, some bikes need it my local GG dealer sez.

I flushed my gearbox out with diesel & ran it on a stand for a min to splash it out & drained well, repeat. Diesel works great to grab all that water.