Fan/cooling problems!

[First time fazer]

Hi Guys, contrary to my handle, this is my second fzs 600 and I'm having a bit of an issue with the cooling system, the problem is, as the bike runs and warms up, it gets to temperature rather quickly, between 8 and ten minutes at idle, the fan will kick on to cool but never goes off. Even on a ride once the fan comes on to cool the water it will not switch off.


I've done a few things to troubleshoot, drained and refilled the system, bled it through thoroughly, I have changed the water pump, which now is definitely working as I can see it pushing the water around with revs at the radiator with the cap off, I have had the thermostat out and tested and is opening and closing as it should, next thing I am going to check is remove and inspect the rad to see if this is blocked at all... But after that I'm at a bit of a loss as to what to check next, any help or direction as to what/where to look next would be much appreciated! Thanks in advance!

[Gnasher]

Sounds like a faulty thermo switch, which is mounted in the side of the thermostat housing, under the tank with a radiator cap on it.

[First time fazer]

Thank you, il check this out also, there are two sensors in the side on the thermostat housing, I'm assuming it's the one with a two pin connection plug? Thanks again

[Gnasher]

Yes, the single it the temp sensor, the larger and double connector is the fan switch. 

[darrsi]

Have you been losing any coolant at all?
Once the bike cools down it should stay around the same level in the expansion tank if the system is all good.


You say you drained and refilled the system, but have you actually cleaned the system using Radflush?


If the waterways are clogged up at all you will end up boiling the coolant then it will dump it out of the expansion tank, which in turn will mean not enough coolant, a hot engine, then the fan coming on.


Putting the bike on the centre stand to check the level of coolant (when cooled down) will immediately give you an answer to the above.

[First time fazer]

I haven't been loosing any coolant that I've noticed, only had the bike a couple weeks! I will give the system a flush and replace the thermo switch and see where I get to from there. Thanks for the advice guys

[darrsi]

I haven't been loosing any coolant that I've noticed, only had the bike a couple weeks! I will give the system a flush and replace the thermo switch and see where I get to from there. Thanks for the advice guys

Do one thing at a time, so you get to pin point the problem.