K75 coolant cap filth/sludge

[matjas]

Hi
As you might remember I have had this bike for a month or so. So relatively new to me piece.
In an attempt /successful so far :D/ at sealing the front of the engine I drained coolant - drained crystal clear, no sediments, no calc deposits, no discoloration of any kind.
Did the job, did the valves, etc and today I wanted to start her up ao needed to fill new coolant in. To my grief I discovered the rad cap covered with oily sludge. There was also some oily, brownish deposit on the inlet funnel'ish part of the filling spout.
Well... didnt like it. Bike rides as new, oil clear etc.
Are they prone to some head gasket issues?
Unfortunately this looks like something is cooking OR had a gasket go on it and this is the remains of what was in the system.

Anyways? Whatdayathink? I will keep riding until winter but then?
Point is I would like to take some trips still but :D if it blows?

Maybe I will do a tankful of gas and then do the disposable test for the CO in the coolant?

Your opinions always welcome.

cheers
matjas

[frankenduck]

They are not prone to head gasket issues.

At the bottom front of the engine is the combined water pump in the front and oil pump behind it. They run on the same shaft and if there is oil in the coolant or coolant in the oil it is usually because the seal between them on the pump shaft is failing.

[matjas]

As we say it in Poland: ride and observe :)

My understanding, perhaps wrong, was that the pump is common for the oil/water BUT, there’s no possibility for the two fluids to mix due to the seal failure - you would get the leak of either through the witness hole. Wrong? 😑

[frankenduck]

 I've seen coolant in the oil before. Right after riding you could see bubbles in the oil sight glass .

[sooprvylyn]

Depending how long rhe bike sat, and how often it sat after rides, could just be buildup of dried fluid in there. Was it actually oily?

[matjas]

Hard to tell with glycol. It was sort of lubricating between fingers. Hope is you could be right and this could be old dried up glycol…
It is hard to believe to drain crystal clear fluid and get problems with head gasket.