Engine oil expansion?

I've got a 92 Kawasaki 750 Zephyr 750 which i think may be leaking fuel in
through the cylinders and raising my oil level. I've been watching it
constantly for a few days after I changed the oil and my question to you all
is; will the motor oil expand and give a slightly high reading when hot??
I'm talking a quarter inch or less over the top line of the sight glass. I
tested my petcock and it is ok, not leaking fuel with the engine off.
Thanks

 

Yes, in fact, oil does expand to a surprising degree. I had the same concern
with my SV650S. I had been filling the sump right to the top line on the
sight glass, and I noticed after shutting the engine off that the glass was
completely covered with oil.

http://www.herguth.com/technical/PHYSICAL.HTM#TE

"Inexperienced people often have an oil overflow because of a
surprising amount of thermal expansion."

Ahem.

"The values of the coefficient of thermal expansion for
mineral oil are near 6.4 X 10-4 degree C-1."

Multiply the CoTE for oil by the temperature rise from cold to hot and by
the volume of oil in the sump, that will give you the change in volume due
to thermal expansion. In my case it was enough (I verified it by measuring)
to raise the oil level as I described above.

 

Ice contracts as it warms through 32F.

There are a number of other materials with negative CTE values, but you
won't find them in your engine oil.

Matt

 

Thanks for all the info.
I've been keeping an eye on it, but I think it was just the expansion that
freaked me out a bit.