Coolant loss but no leaks!!

[Capt]

Don't know where it's going, loosing approx 100ml per 300 miles with no visible leaks at all, anyone experienced the same??

[Dave48]

I take it youve checked your oil to make sure coolant isnt getting into it (head gasket?) Any small splits in hoses? Bike overheating?-(Thermostat sticking).

[Tmation]

Have you checked the exhaust/EXUP housing area? You can get a leak from the oil/water pump (which is inside the engine), it drips from a small hole in the sump and then burns off on the exhaust leaving a mark. Fingers crossed that it isn't as its a big job to change.

[Capt]

Just checked the syringe scale, it's more like 50ml it's loosing.  Even so I still cant see any drops/leaks anywhere, oil looks fine in the sight glass not sure where it would settle though. No drips or green residue anywhere, I have done the Coolant bypass and dropped & drained the rad earlier in the year, could it just be trapped air slowly working its way through I wonder.  I guess a yam dealer pressure test would show a leak somewhere?

[eddie]

just keep topping it up .....next oil change will show if water present...the rad pressurises its self in normal use  if it were holed you would know by now

[red98]

check the oil filler plug on the underside....if you have mayonaise there thats oil mixing with the coolant.....if theres air in the system it could be pushing the coolant out of the header tank , try running it without the coolant cap on , you should see air bubbles trying to escape if theres air in there,when the caps on and sealed theres nowhere for the air to go except the overflow......

[Timabusa]

Just changed all the hoses on mine for nice blue Samco silicone hoses then refilled the rad ran the engine for a couple of minutes to check for any leaks once that's done i run the motor quickly with the rad cap off i found that cures any air lock in the system!

[Capt]

Thanks all for your comments, if there was a seal/rad/hose leak I suppose it would be leaking on the floor overnight??................it's not as yet so will keep filling it as suggested.  It's feckin odd though & one massive pain the ass if it's leaking internally!

[red98]

Thanks all for your comments, if there was a seal/rad/hose leak I suppose it would be leaking on the floor overnight??................it's not as yet so will keep filling it as suggested.  It's feckin odd though & one massive pain the ass if it's leaking internally!

have you ever had any overheating problems that may have damaged the head gasket/head ?

[Fazerider]

... if there was a seal/rad/hose leak I suppose it would be leaking on the floor overnight??

Had the rad spring a leak on mine last winter. Never noticed any drips on my garage floor, presumably they'd evaporated and the hole was small enough that the flow stopped once the bike had cooled. Was only aware something was amiss because of the smell every time I parked up after riding. 

[Capt]

Thanks all for your comments...........

No signs of salad cream on the oil filer cap, still nothing dripping leaving the rad cap off for any siphoning etc.


Will a rad pressure test check the whole coolant circuit or just the rad?


If its goin to blow up so beit, the last 300 mile ride I had on Saturday in North Wales without the wife with the Ivan's Full Monty, with the FZ6 larger rear sprocket it went like a bat out of feckin hell.  3000 grins all the way, what a machine!