Good advice! I will try this again when the radiator cools off.The problem with the cap, is not the spring, it is probably the lower rubber that is marked by the radiator. Change the rubber ( or turn the rubber over while waiting for a new cap or rubber)... but don't buy a cap with more pressure. Without discussing the design of the "cooling system" and the working pressures ... if you change the cap for another with a spring with more pressure ... and the base where the rubber closes, is the same (the same contact surface) ..... the rubber will deform prematurely, conclusion .... it will last less
Thank you for this good advice. I replaced the coolant before leaving on this trip and everything looked good. When I get home I will flush the system and put a new cap on to see if the problem will be solved.I might think that what you found in the radiator neck migh be Coolant residues, (when was the pervious time you looked in to the radiator cap, for sure, too long ago) so it migh be there due to accumulation and of course the rubber of the rad cap. My recomendation is as said look in to the cap and as soon you can do a coolant replacement and take a good close look in to the coolant remove to see if there is any other indicator of failures (look for color, deposits, other different things) and compare it with the new coolant to be used. Using a higher pressure rad cap I would not recomend because you will increase the complete cooling sistem pressure and will harm your system somehow.
Hope you can solve your problem and keep us inform on your findings.
Have a great weekend.
I just removed most of the excess coolant from the reservoir. This is how it looks. There was black crud floating in there but it doesn't look bad...If this were my bike i would do a full flush with a few gallons of distilled water and check all the lines for blocks. Maybe also a new cap.
This is a good example of why its great to drain your coolant into a clear container like a clean 2l bottle. You can see everything that comes out, helps to catch things like this.
Strange, i agree it does not look like oil or a hg issue at all.
Could be, but this is why most manufacturers recommend silicate free coolants these days. If there was silicate containing coolant in there that might explain it. Did the coolant you used say “silicate free” on the container? Make sure whatever you use next has that statement. Your cap may actually be ok, that crud might have been preventing the lower seal from seating correctly.silicon residue im thinking . seen it before , not sure why it does it ,thinking some coolant has silicon in it and that's why the residue. just my best guess .
I honestly don't know if the coolant was silicate free. It's Castrol motorcycle specific coolant. I changed the orientation of the radiator cap around with the text on the cap facing the bike. I have the feeling the cap doesn't close evenly. There is also play between the seal and the spring. Somehow doesn't feel right...Could be, but this is why most manufacturers recommend silicate free coolants these days. If there was silicate containing coolant in there that might explain it. Did the coolant you used say “silicate free” on the container? Make sure whatever you use next has that statement. Your cap may actually be ok, that crud might have been preventing the lower seal from seating correctly.
Sent from my iPhone using Tapatalk Pro
Åh okay, was not aware of thatYamaha runs two seals on their water pumps with a void between the two where the little drain hose attaches. Oil leaks into the void and out the hose, coolant leaks into the void and out the hose. Real slick design I think.