2007 cooling fan not coming on

I posted about this on my intro in general discussion but adding here in hopes of more input.

Thanks to member sfdownhill a little $, and a TON of work, I replaced the engine with 95,000 miles on it with one that has only 7,000 miles on it.

Everything is a-ok, except she's getting way hot without the radiator fan coming on. I tried burping the system, and i *think* i got all the air out. The Thermostat could be stuck, or there is air in the system? The right radiator gets warm to the touch, the left one not very warm at all. Especially in the upper area where the fan switch is. I do get a temperature reading on the dash and the radiator fan wire is attached.

The fan does run if I ground it to the frame.

What's more likely? Air in the system or bad thermostat. I REALLY don't want to pull those throttle bodies again. :sour:

 

Cooling system sensors consist of thermostat, coolant temp sensor, and coolant fan switch. Check'em all

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i'd put money on thermostat.

 

Would definitely be if the hose was cold and engine was overheating

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Thermostatic switch.

That would be an easy fix.

 

I've replaced the fan switch and the thermostat with new parts. The fan will run when the lead to the fan switch is touched directly to a ground. I pulled both radiators and run water through them to be sure they're not clogged. I've burped the system as much as I can or know how via the lean the bike over method, blip the throttle method, squeeze all the hoses method, and spill proof funnel method. No joy. Temp still climbs to 240 degrees with no action from fan and I shut the bike down.

The engine only has 7000 miles on it. I can't imagine the water pump being bad. It's not leaking or making any noise. And when I pulled the outer cover off, the blades look fine and don't spin freely, that is they're firmly attached with the engine. Both radiators get hot, although via infrared thermometer, the left is slightly cooler. Neither is so hot I can't keep my hand on it even when the dash is 220-240 degrees. I'm using Prestone DexCool, if that makes any difference.

Any other thoughts?

Thank you!

 

1.) verified the ground wiring in the wiring harness to the temp sensor is actually grounded
2.) hoses hooked up correctly
3.) is it visually evident that the fluid is moving through the system when the engine is at operating temp, i.e when the thermostat should be open (can be seen with rad cap off)
4.) is the movement of the water pump impeller verified by manually spinning the engine over with the plugs out
5.) are you sure the water jacket isn't plugged
6.) have you heated the thermostat and the temp sensor to verify proper operation at temperature
7.) are you seeing an increase in fluid into the overflow bottle when the engine gets hot

 

8.) is the ground wiring for the fan switch verified to be properly connected and grounded through the wiring harness
9.) is the fuse blown to the fan motor
10.) have you replaced the rad cap

That should eliminate a few possibilites, or send you on a snipe hunt. Hopefully, the former and not the latter.....

 

VICTORY!!!!!!!!! :chaingun:

Thanks NorcalBoy for inspiring me to check everything! I went back to the garage determined to dismantle every part of the cooling system and check every passage and hose I could to make sure there were not obstructions and make sure the water pump was turning.

When I got this engine, there were plugs in just about every orifice. The coolant hose that goes from the water pump to the engine block was missing. I swapped the hose over from the old engine and apparently this rubber plug was either missed by me or so far up in there, I wouldn't havee noticed. Plug in place:



I drilled a hole in the rubber stopper, drove a screw into it, and yanked it out with some pliers.

Showing location using old engine:





I just took her for the first ride since the engine swap (sans body work). So awesome!!!

 

Very nice, glad it all worked out for ya. Enjoy the ride!

 

Hey - great news Brad! OOTV pointed this thread out to me and wow did my heart stop. I can definitely say thanks to the collective and especially NorcalBoy from both of us. Sorry for plugging up all the orifices with those test tube stoppers, but I didn't want the shipping carrier to kick our project to the curb for leaking. Can't wait to hear about the rides you're going to take on that RWB.

 

Could be fuse, it happened on a vfr 2000 model I had