Fan not working?! - .: XT660.com

plank · # 1 14-09-10, 16:57

Hi Guys, hope everyone is doing well.

I recently noticed that my XT's fan kicks in when the bike already seems too hot, as the water started pushing out at the radiator cap...and the fan still did not kick in. The temperature light did not go on, but it does glow when i turn on the ignition. Ive checked the fan motor by connecting it straight on 12V, and it works fine. I then checked the switch that goes into the motor, im not sure what you call it, but i guess its something like a temperature/fan switch. I took this switch out and put in into warm water...and then realised that i dont know what it should actually do when it is warm/boiling water, and how to test if its working fine or not.

Can someone perhaps advise me as to how i can test this switch, or is there something else i should look at? O yes, and the fan's fuse a the battery is fine.

Thanks a lot
Schalk

InkaJoe · # 2 14-09-10, 17:25

The fan kicks in quite late.
At arround 90 C oil temperature and / or 115 C water temperature.
Therefore, testing the thermo sensor is difficult with boiling water (~ 100C).

dazmatic · # 3 14-09-10, 18:01

During my testing, I discovered the fan on my bike (XTX) turns on at around 105C as I watched the temperature reading increase on my PCV software.

The 'switch' you pulled out, where did it come from?

Was is on the right side of the bike, same sort of height as the TPS on the back side of the cylinder and made of brass?

http://4.bp.blogspot.com/_vE1-EGFNds...660+Engine.jpg

At the top of that pic, in the middle.

If its what im thinking of its the temperature sensor.
As it heats up, the voltage across it drops so what you can do it put a multimeter across the 2 pins on it and measure the resistance.

It should be around the 2000 ohms mark at 20C and about 180 ohms at 100C

plank · # 4 14-09-10, 20:17

Yes thats the switch i was referring to. :-)

Thank you very much for the feedback, its much appreciated, i'll measure the resistance as soon as possible.

Cheers
Schalk

maxwell123455 · # 5 14-09-10, 21:32

Quote:

Originally Posted by plank

Yes thats the switch i was referring to. :-)

Thank you very much for the feedback, its much appreciated, i'll measure the resistance as soon as possible.

Cheers
Schalk

If its your fan unit that is gone Kev just posted two links to fan units on the ebay section at the bottom. My fan unit broke about 2 weeks ago but i finally got one from germany.

dazmatic · # 6 14-09-10, 23:31

Think his fan is fine so he says, tested it on a 12v source.

How old's the bike? How many miles?

I'm thinking about the radiator cap itself, whether thats faulty.
They're designed to be able to handle a certain pressure, thats how the coolant is allowed to go above 100c without boiling because its kept under pressure.

If the cap is faulty or doesn't produce a seal well, it may leak and boil over.

Might be worth having a look at the radiator cap, checking the condition of the seal and sealing faces.

Kev · # 7 15-09-10, 02:13

The radiator fan can be tested through the diagnostic screen, it can be turned on through the screen which will test the complete wiring circuit of the relay, wiring & fan.

You can measure the coolant temp sender resistance at a given water temperature, to see it is in spec, refer to the workshop manual.

Pressure test the cap & cooling system for leaks, as Nigel mentioned the cooling system is pressurizes to raise the boiling point & any leak will lower the boiling point to below the switch on point of the fan & the fan will not run. I have not heard of any cap faults, but in the past we have had cooling system leaks from water pump seals & loose hose clamps.

plank · # 8 15-09-10, 22:10

Thanks for the assistance guys.

Its a 2006 model with 40000km on the clock. The water does not boil from the radiator cap, but from the over flow bottle next to the radiator. Unfortunately i havent had the time to check the sensor and its resistance or do a pressure test, which will probably be the most conclusive as to where the problem is, and if the cap is in fact sealing 100%, but will try and get to that in the next day or two.

Im pondering whether I should connect a resistor eg 100ohm at the sensor to enable the fan to switch on a tad earlier than normal...but i guess Yamaha made it that way for a reason.

Thanks again for the advice, its much appreciated .

Kev · # 9 15-09-10, 23:20

Quote:

Originally Posted by plank

Thanks for the assistance guys.

Its a 2006 model with 40000km on the clock. The water does not boil from the radiator cap, but from the over flow bottle next to the radiator. Unfortunately i havent had the time to check the sensor and its resistance or do a pressure test, which will probably be the most conclusive as to where the problem is, and if the cap is in fact sealing 100%, but will try and get to that in the next day or two.

Im pondering whether I should connect a resistor eg 100ohm at the sensor to enable the fan to switch on a tad earlier than normal...but i guess Yamaha made it that way for a reason.

Thanks again for the advice, its much appreciated .

To run the fan earlier you need less resistance not more.

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