Hi ,

My hot check engine is only coming on when I’m riding 3000 + rpm. If I come to a stop sometimes the fan is already on sometimes it kicks on few seconds later and the hot check engine warming goes away. I had left it running at the house for 30 minutes prior to taking it for test drive and the fan comes on around 200f and off around 185f (using a heat sensor gun pointing at the elbow on the rad hose just above the heat sensor. When I got to my garage it was flashing hot and I grab the heat gun and it was showing 198f.. maybe 20 seconds later at idle fan kicks on and kicks off few minutes later.. left it run for 10 minutes and seems to cycle fine.

The only thing I did was replace my rad fan with a new one as my old one started to make noise from the bearing. (Radiator is clean as a whistle so is the screen in front of it… the fan is sucking a lot of air too)

It’s a 2004.5 Sportsman 500 HO. There is no sensor on the radiator just the heat sensor on the engine above the oil filter. Do you think it’s that sensor causing this? It’s cheap to replace. Anyone else seen this before?

I’ve already had the ECM replaced about 4 years ago due to fan running all the time and it showing hot check engine. The radiator is full and the bottle is half way between minimum and max… when it warms up the bottle is around max. I didn’t have this issue until I replaced the fan.

Thanks for any help

 

it does seem strange as the fan is only powered with 12 volts when the sensor is pushing out the signal. i would think the fan shouldn't have nothing to do with the new issue assuming you put the correct part in. i would just change the sensor to see what happens. i would say it sounds like air in the system, but you didn't change anything there as well,