[rob310gs]

I know this has been covered a bunch of times on here but I've never got an definitive answer on what's going on. Today at just over 3k miles I noticed one drop from the longer tube. I'm posting a pic and one hangs a bit lower than the other. My bikes a 21. I can't say I've noticed that before. It was a fairly hot day and I just rode about a half hour at hiway speeds. What is the leak and is that small amount acceptable? Also I'm posting a pic of a reservoir under the guage cluster. Is this the coolant overflow level? I didn't see any level indicators.

 

[Britmech]

That looks like the pipe from the water pump and should not be leaking or dropping any coolant mechanical seal could be poor.

 

[bbbelanger]

Yes that is the coolant overflow tank and the plug used to top it off. On my 2018 R , the reservoir has Min and Max levels that are not very easy to see, but the level should be slightly below the middle.
In my experience, a low level and “some” drip are not reason to panic. I mean there is a reason there is an overflow tube in the first place…

I would recommend a search for Hasselmann’s thread on the subject for a real life documented bad water pump seal. (And the replacement procedure).
And in any case, if it’s a 2021, let the dealer and warranty take care of it if necessary

 

[jsdriscoll]

I just experienced this on my R. I had the bike taken to the shop by BMW roadside assistance and it was a coolant overflow leak. They said it happens on new bikes when it gets warmer out. I bought the bike in December lately in Texas it's been over 100º f.

 

[ARBOLMANO]

Well, I’m in the club. Went to change oil and found coolant tracks on skid plate. Lower hose is water pump, higher hose is coolant overflow. The double check was to let it idle and reach operating temp (fan comes on) then drip starts…….the level has only dropped tank to half.
No loaner from dealer but they are sending a truck to fetch it up……

 

[ARBOLMANO]

The man, Hassleman that is really posted great write up on doing the deed yourself on adv
post#9067 Thanks there H man

 

[hasselman]

The man, Hassleman that is really posted great write up on doing the deed yourself on adv
post#9067 Thanks there H man

Take it easy, ARBOLMANO. I'm blushing from that kind of words. We Finns are a humble sort of people ;-)
But thank you for the recognition.

 

[ARBOLMANO]

So since I’m not going riding after finding a water pump leak, I went and installed a voltmeter USB. In the process, was able to get more intimate with the 310. Two things I saw.
one being I can fit my cooling system pressure tool to the radiator, once Tupperware out of way. This would be the very best way to test for leaks, though not how I would do it.
The second and perhaps most import to many, the coolant recovery tank has no overflow drain line attached! At least on my 22…..This means any coolant coming out of a hose is from the water pump weep hole and is a leak that must be addressed. Recovery bottle if overflowed (over filling, blown head gasket etc) will dribble from the top of bottle making mess. A leaky pump should not be ignored, unlikely it will fix self.