Bike losing coolant and oil on roadtrip - please help me :(

[ItchyMike]

20210921_094945.jpg

Hi, guys.

So here we are somewhere in the middle of Spain where all of a sudden in a gas station I noticed my bike dripping what seems to be a misture of oil and coolant through the airbox ( see photo ).

We did 100km in the highway between 100-110 km/h before.

We are travelling with 2 nx250 and we noticed something odd:

My bike reaches 100degree Celcius in the radiator gauge and quickly drops to 60, and keeps climbing back to 100degree and back to 60 ( Is the fan engaging in the highway? ). There is no coolant in the oil in the engine and no oil in the expansion tank.

The other problem free bike maintained a steady 80 degree celsius during that course.

Any idea of what could possibly wrong? Gasket problem? Stuck thermostat?

I just did 70km after this at 60/80 km/h and this time the problematic bike kept a steady 80 degree celcius with only some little drops.

Thanks!

[scrambler]

ok, I have to do some brainstorming first - what you should check first - the condensate from the drain hose should be drained regularly. Otherwise it will run back into the air filter box over time. So drain, clean everything well and see whether any more oil gets into the air filter. By any chance you haven't overfilled the engine with oil?

[scrambler]

My bike reaches 100degree Celcius in the radiator gauge and quickly drops to 60, and keeps climbing back to 100degree and back to 60 ( Is the fan engaging in the highway? ).

second thought - the chinese radiator gauges are very unreliable, I had massive loss of coolant after a short time of usage. switch the gauge with the radiator cap of the other bike and try if its getting any better.

[scrambler]

My bike reaches 100degree Celcius in the radiator gauge and quickly drops to 60, and keeps climbing back to 100degree and back to 60

that is actually indeed odd - nobody reported something like this before. If its not a mad temperature gauge I guess it could be a stuck thermostat, that would explain the steep temperature drop. In this case you can try to drive home, make sure there is always enough coolant and keep an eye on the red warning light - if it’s on take a rest and allow the engine to cool off. Is the fan running at 100C°? It should.

If you have the means to you could cut off the top and the bottom of the thermostat and remove the valve. Then you have a free flow for sure. Maybe a o-ring gasket the size of the thermostat works too.

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As for a blown gasket I guess is highly unlikely, since I heard of only one case in 15 years. And then it’s simply consuming coolant, without blowing it into the air filter.

[ItchyMike]

Thanks! I will take everything in account. The fan engages indeed at 100 degrees, and I never got the temp light to come on ( unless it is not working ).

I think both gauges are working OK because in both bikes the fan engages at the 100 mark in the gauge exactly.

The coolant loss seems to come from the expansion tank because there were marks of coolant in the left engine side.

The engine is making a slight ticking sound, which hasn't got worse in 140 km.

No further apparent more coolant or oil loss in 140km.

I will try to drain that tube now.

[scrambler]

The coolant loss seems to come from the expansion tank because there were marks of coolant in the left engine side.

ok, then it's an untight temperaure gauge (or the expansion tank or hoses are untight) - maybe you could get a radiator cap in an automotive shop, the ones with big head fit.
stock is 1.1 pressure, but 1.3 should work, too.

[ItchyMike]

Ok, so I drained the tube, a lot of gunk came out of it...

20210921_125413.jpg

Is ok to travel a few kms without the cap to clear any moisture?

[ItchyMike]

The coolant loss seems to come from the expansion tank because there were marks of coolant in the left engine side.

ok, then it's an untight temperaure gauge (or the expansion tank or hoses are untight) - maybe you could get a radiator cap in an automotive shop, the ones with big head fit.
stock is 1.1 pressure, but 1.3 should work, too.

I mean the coolant loss came from here:

20210921_125804.jpg

Perhaps I have not used the correct term. But no more coolant loss for the past kms...

[scrambler]

Ok, so I drained the tube, a lot of gunk came out of it...

20210921_125413.jpg

Is ok to travel a few kms without the cap to clear any moisture?

I would not do that because of the environment (you don't want Greta to visit you ). It's also not necessary, try to clean the air filter housing as good as possible.

[scrambler]

I mean the coolant loss came from here:

download/file.php?id=11261&mode=view

Perhaps I have not used the correct term. But no more coolant loss for the past kms...

it's ok, that's what I meant, too. If the radiator gauge is untight (maybe thats an unprecise term - I meant if it can't hold the pressure of 1.1 and opens at much lower pressure) too much coolant is flowing into the overflow reservoir until it overflows Usually the coolant comes out of the tube at the bottom of the engine.