Mysterious coolant leak

FizzyDiver

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A while back, I noticed that my bike was running a little hot. Checked the coolant level and it was nearly empty! I refilled and about a month or two later it was noticeably lower. I kept tabs on the level and tried to find any leaks but couldn't find any. Has anyone else had this problem?
 

FIZZER6

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If it's not dripping from anywhere when hot I hate to say it but on cars 95% of the time you have coolant loss the culprit is a slow leak in the head gasket which allows the coolant to slowly burn out the exhaust with no smoke obvious. For your sake I hope it's just a leak on a coolant hose or your coolant drain plug.
 

TownsendsFJR1300

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Its not unusual with the numerous heat cycles for the hose clamps to loosen just slightly.

With the engine heat, the very little bit that may sneak by evaporates before it hits the ground.

IMO, I would check / snug down EVERY coolant hose clamp including the oil cooler, back of the engine, radiator, etc. Most likely you'll find several of the clamps not terribly tight...

Also, look closely at the radiator for any DISCOLORATION/ build up should you have a small leak.

Please post what you find...:thumbup:
 
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outasight20

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It's possible you have some air bubbles trapped in your cooling system. You can check this by filling up the overflow to full, opening the radiator cap, and starting the bike and letting it run until fully heated up. Any bubbles will work their way out through the open cap. Then shut the bike off, replace the radiator cap, and let it fully cool. It should suck some coolant out of the overflow. Then refill the overflow to full and keep an eye on it. With just 6,000 miles I doubt you have an internal leak through the head gasket.
 

oaks

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Where were you checking the levels -- in the radiator or the plastic reservoir tank?

Since you mention in another post, you need to catch up on maintenance, I'd start with a coolant flush and change, to include the reservoir tank, so you have a good baseline to troubleshoot.

Adding to other posts here, there was a recent thread where someone had a minor leak caused by corrosion on a hose fitting. Removing the hose and cleaning the aluminum fitting fixed that. (I can't find that post with pictures at the moment.) Look for wet-looking or sticky areas around the hoses.

Edit: the thread I mentioned: http://www.600riders.com/forum/fz6-general-discussion/51977-water-pump-hose-leak.html

Additionally, I found the hose clamps on the water pump hoses pretty loose when I changed my coolant earlier this year. Surprised they weren't leaking.
 
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FinalImpact

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Also if the mix is mostly water it will evaporate from the reservoir. A 50/50 water/glycol mix will redice the evap rate to nil.

When wash it flushed and completely replaced last?
Also, when was your last oil change and how did the oil level and color look?
 

FinalImpact

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One more thing, a bad radiator cap could allow it to push water out of the overflow and you loose it without record as it overflows the reservoir.
It can do this and not overheat in some cases, so inspect the cap well. Any debris caught in the inner seal or that inner valve can cause this. Also when it cools down it would not draw from the reservoir.
So until you get this figired out, check the levels at the cap and resevoir.
 

FizzyDiver

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Hopefully it is just a hose. Not the, dare I say it, head gasket... gulp. With the holiday weekend coming up I'll have some time to inspect closely. Thanks.
 
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