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Coolant level drop when hot but rises when cold

1393 Views 4 Replies 5 Participants Last post by  clutchcrusader
After a coolant change.

The coolant level in the expansion bottle is on the high marker (when the bike is cold )
The coolant level in the expansion bottle drops to the low marker(when the bike is hot )

Service manual states, do don't overfill past the high marker....please explain what to do
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The coolant in the motor expands as it gets hot and gets pushed to the reservoir making the level go up. When it cools down, the coolant contracts and should pull it out of the reservoir. And the level should go down. If you just changed the coolant then the level will go down until the air is out of the motor.

You can fill the reservoir to whatever level you want, but if you over fill the coolant it will just piss out onto the ground through the overflow hose when hot and be wasted. Or cause you to crash if it gets on the rear tire.

If it's already near either of the marks, I'm with dricked and leave it alone.
Never noticed level changing comparing hot/cold; I believe I check it when kinda cool, but level certainly does drop over time. I always over fill it as takes very little so easy to go over the upper mark by a couple inches. bike doesn't care about it.
Mine did the same after I had water pump gasket fixed.it kept getting lower until all the air was gone.
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