Cooling problem - water is boiling - Kawasaki Forum ::
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post #1 of 4 Old 07-19-2013, 07:17 AM Thread Starter
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Cooling problem - water is boiling

Checket the Whole system. Fan, fan "switch", temperature measurer, thermostat. Everything seems OK in accordance with the manual. -Or almost everything.

The thermostat: Checket it and its not stamped/opereated as mentioned in the manual, so I dismanteled the housing- took the thermostat out and reassembled the housing.
I really cant figure out why the manual says that the thermostat should lie between 69,5 and 73,5 degrees celcius. On this particular MC and on another Ive checket (I have 5 GPXs) the thermostat is stamped 82 degrees and Ive checked both in heated Water. Both opens at approx. 85 degr. and is fully open at 90 degr.

The MC runs fine and if kept on centerstand/Idle at approx. 800 revs/min it heats up to 98 degrees celcius and the fan starts. At 2500 revs/min the temp is 96.
The mc kan be ridden 15 km at 60 - 110 km/h without any bigger problems - but is warmer than normal though. -BUT if I give a 3/4 - full throttle it heat up so much that the Water starts boiling BUT the fan doesn t start and its very hard to get Down in temperature.

I think the above indicates a thermostat problem OR defective waterpump - though Ive never heard of a defective pump........ the thermostat is removed from the housing, so it can t be the thermostat.

Any comments on what I might have missed ?(except for the waterpump Ive not checked yet).

Ive tried to the same as on cars squeez the rubber cooling hose, rev it and feel if the hose gets stiffer. Maybe I can feel a Little stifnes but not much. Any other way except dismantling the pump (all in all Im not especially fond of timeconsuming Work - will rather ride my bike(s) ).
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post #2 of 4 Old 07-19-2013, 08:45 AM
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First of all, You must use good coolant, I mean really good one.
Second thing is to vent system properly. Pour coolant in to radiator
and squeeze the big hose to all boobles come out.
After that start motor with out radiator cap till get hot.
All boobles should come out. If that wont works. Try to make fan switch
or just wrap the exhaust with bazalt tape.

You might use better engine oil with higher second number 10W50 for example
and only full synthetic.

Thats for know. what I have on my mind.
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post #3 of 4 Old 07-19-2013, 09:08 AM Thread Starter
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Its a problem arisen during the "stand-still" in Winter, so nothing has changed. Concerning coolant Theres not much to get here. ive also tried with almost only Water as Water is much better transferring heat than the mixture Water/coolant, What I meant was dont think itshere the problem is. btw I have 5 GPXs and have had MCs for a long time and Im a do-it-yourself-guy (besides my ingeneer graduate) so Im pretty familiar with mechanics and chemistry, but Im afraid its not enough this time......
As I said I have to check the waterpump somehow, but I cant imagine its here there problem is..... (still heeeeelp ;-) )
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post #4 of 4 Old 07-19-2013, 10:31 AM
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Squeeze the lower hoses. Have the radi cap off to watch any bubbles. Take the radi cap to a radi repair shop or buy a new cap for some honda car, toyota, etc. They are that universal in other words. Cap has to hold 15psi and let off. If it can't hold the 14.7? = Boil

Known to be at tech thread abuser. I like lying to animals too.
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