2001 Honda Shadow radiator steams after warming up

Greetings,

I have an '01 Shadow with just over 11k miles on it, and at the end of
last summer I flushed the radiator since to my knowledge the fluid had
never been changed. Since then, the radiator will steam after the
bike warms up, and at one point the temp bulb came on (there is no
needle indicator). When it steams, I check the fluid and it appears
to be low, so I add some, but I can't for the life of me find a leak
on any of the tubes going to/fro the radiator.

Also, it appears the old radiator fluid may have gotten burned to the
inside of the fluid reservoir. When I look in the filler tube I can
see a green film lining the inside of the reservoir and I'm not sure
if that's affected any fluid flow.

Any ideas? TIA!
-drew

 

That green slime tends to accumulate in the overflow bottle because the
coolant is exposed to air there much more than in the radiator...........and
it's difficult to completely drain without taking apart. Usually not a
problem.

As for the leak, you need to get pressure in the system without getting it
HOT........since the leak turns to steam when hot making it hard to locate.
Either run the bike a short time, stop and look for leak OR get a leak
tester, which is a pump that attaches in place of the radiator cap to
pressurize it when COLD.

From your description, my guess is the leak is in the core itself.
OTOH, it showed up after you messed with it so it's likely that you messed
something up......like didn't get the drain valve closed tightly.

Good luck.

 

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The first thing I would check would be the cap; specifically the
condition and alignment/placement of the rubber gasket in the cap. It
may have either deteriorated over time, or may have become misaligned
as you removed it.
It spring may also have just become weak over time.

Other than that, a pressure test of the cooling system is in order.

Wudsracer/Jim Cook
Smackover Racing
'06 Gas Gas DE300
'82 Husqvarna XC250
Team LAGNAF