overheating troubleshooting
 

Hi All,

I've been problems with my fan not going on when it reaches temperatures over 220 (or any temperature). Fan was coming on fine for a bit then it just quit. I checked the fuse (ok), and then checked the fan without the switch and the fan worked. So I assumed a faulty cooling switch and replaced it (with Nissan Pulsar switch). I started it up and took it out to get up to temperature, and the fan still doesn't go on.

When I parked my bike and started looking around, I noticed a coolant leak from a hose down low. I haven't checked coolant levels (it's still too hot from my ride), but if they are low would this effect the switch and the fan?

I'm trying to figure out what I should be troubleshooting next. I'm guessing the thermostat is ok because that's reading engine temps. Should I flush/refill coolant next? Other things I should check? I realize there's still a possibility the switch I installed is bad, but I'm trying to figure out what else it might be.

Any ideas would be much appreciated. Oh, it's a 2002 f4i.

Thanks in advance.

Make sure the ground is good. Is it a single wire switch? If it is, Teflon tape shouldn't be used and there needs to be a ground from the radiator to the frame.

Thanks 74 demon for the reply. It's a two wire switch, one I connected to the fan and the other to ground. I ground it on the radiator ground at top left corner. Does ground need to be direct to frame? the part pic is below
https://cimg1.ibsrv.net/gimg/cbrforu...f3171b928f.jpg
ts119

The radiator is supposed to have a ground to the frame. It sits in rubber grommets so it's not grounded by itself. Either make a ground wire for the radiator, or put your switch ground to the frame.

Thanks again 74demon. I ran the bike to 225 -230 and the fan didn't go on. When I got off I kept the bike running and redid all the connections at the fan/switch. Fan went on! I have the ground to radiator as you mentioned, just did a little jiggling and it kicked on. Might need to recheck my soldering work. I tried it again today and it worked again from a cold start. I'm hoping that is the end of it. I'll let you know if anything else happens.

Thanks again for the input, much appreciated!

The magic of a little 'jiggling', glad you round the problem.