[Sigmaman]

I flushed the coolant today and replaced it with Engine Ice. I let the bike idle for about 5 minutes but the fan never came on. I rode the bike for about 10 minutes and still didn't come on. The temp outside is around 60-65 degrees. The bike ran normal as usual. Is this normal or is something faulty with the fan?

Additional info: I installed a 2 Bros slip-on about 4 months ago. Not sure if that makes a difference.

 

[Axel kain]

My ESPN is getting that you have a 1994 ninja 250. am I correct to guess this?

I would expect that since you have a more effective cooling fluid in the system, maybe the outside temps are enough to keep the fluid at the proper working temp. or maybe you disconnected a fan switch by accident!

 

[StarGate]

Or it could be one of the few models that has a problem with air getting trapped in the system and preventing water from circulating. Is the radiator getting warm?

 

[Sigmaman]

My ESPN is getting that you have a 1994 ninja 250. am I correct to guess this?

I would expect that since you have a more effective cooling fluid in the system, maybe the outside temps are enough to keep the fluid at the proper working temp. or maybe you disconnected a fan switch by accident!

Sorry, forgot to include what bike I had. 2006 Ninja 650R

 

[Axel kain]

thanks!

StarGate also has a valid point! if the sensor never see's the temps rise (if its trapped in an air pocket) then you can cook your engine and never even have the rad. kick on!

research time!

 

[ChevelleSSLS6]

Supposedly the coolant reservoir is the highest point in the cooling system. Squeeze the radiator hoses and sometimes you can feel (or see) air bubbles come out.

If all is well, get a thermometer of some sort (I like the ones in the multimeters) and fire it up. I'll assume the outside of the engine case shouldn't get hotter than typical "max coolant temp" (265*F) but I'd say 230* to be safe for the engine case.

I would measure the temps below the head (big thing with small circles on the side) where the cylinder (and therefore combustion) is. It's a pretty small area. Measuring the temps of the side covers will do little and are a better indicator of oil temps.

The stock fan should turn on before the coolant reaches 220*. Most are set up to turn on between 190* and 220* F.