Sorry if this drones on, trying to give the most accurate info, if you don't know anything about overheating/cooling system, you might want to move on...anyone else, I truly appreciate any insight.

2 weeks ago, went out on the trails(105 F with the humidity) and lasted about 30 mins till hot light came on. Stopped and turned off bike. Light went out after a few minutes. Drove again. Light came on, stopped, and it went out. Fan was coming on. Third time light came on, I kept riding, lightly, fan came on, light went out. Left the trail, on to the street, light stayed off...

Stopped for lunch (15 mins after) noticed a bit of coolant coming out of rear fender overflow tube. It stopped, and rode home.

Checked things at home, everything normal.

Fast forward to today. Trailered to an awesome trail system about an hour away. Just stopped raining, so was probably 86f with humidity..very damp..but not stupid hot

Lasted about 35 mins before light came on...

A few facts:

Using Motocool by motul.
Everything topped up.
Burped properly, no Air


Got back to truck. One thing I noticed is that I could easily pinch coolant hose ("top one")with 2 fingers, with engine running... Would have thought there would be more pressure there. At least be harder to pinch

But light came on if I left it heat up a bit again, at idle (normal, heats up fast at idle)

No leaks anywhere..

Coolant full in Rad, so no burning coolant (and had no white smoke)

Got it home. Drained coolant, pulled impeller cover, fins good and sharp, and can't move it by hand (expected, I guess). I wasn't about to try to heave it with a screwdriver.

Pulled thermostat (original, 2011)... All I had time to do is boil kettle (apparently about 200 F) and it seems to only open "halfway". Is this normal? Or is stat pooched? I ordered new thermostat but still wondering


Getting pissed now.... Don't think it's the 351 kit, as others are running it in MUCH hotter temps with no problems. Just banging my head now...

Help...

*********Update**********£

So, just an update for anyone else that may experience the same.

Changed thermostat, fan sensor switch, added Motul motocool, and everything seems to be back to normal. Fan comes on BEFORE the light, and light didn't even come on the last 2 rides.

Fingers crossed!

 

Was the fan running a lot? It is also controlled with a temp sensor. If the temp was really high I'd think the fan would run near full time. Saying it might be the light sensor.

When in doubt put in a new thermostat.

Ultimate question - thermostat in the right direction? No insult intended, just saying it's possible. You might consider the Thermo-bob which evens out the cooling up to the point of the open thermostat.

You could pull the thermostat and see if it still heats up. It will take a long time to warm up, but no restriction.

 

Acruelly, no, the fan wasn't running that much, which kind of surprises me now that I think about it..it did come on but I wouldn't say alot.

Was in the right direction, I double checked just in case. I thought about the Bob, but that really doesn't do anything for high temps if something else is causing it

Might just try no thermostat for a bit... see if that helps..

Thanks 678!

 

The sensor for the warning light could be malfunctioning and triggering the light at too low a temp. From your inspections, everything else looks good.
I have never heard of any of these bikes having a temperature problem. My fan hardly ever runs, sounds like yours is the same.
Is the overflow spitting hot radiator fluid into the resevoir? If not, I bet it is the 'light' system.

 

I haven't seen any fluid spitting into reservoir, and the more I think about it, you might be right..

If I understand correctly, it's supposed to be fan on first, then light comes on if it doesn't cool down.

My light comes on first, for a good amount of time, before the fan comes on. When the fan DOES come on, it only comes on for a brief time maybe a minute or so)and light goes out..

Fark it, gonna replace everything lol...

 

Don't run no t stat, I've experienced over heating on previous vehicles with no t stat. You need enough restriction to slow the coolant enough to enable proper heat transfer. Typically no t stat causes it to take for ever to warm up then after it's finally warm it slowly runs hot or even over heats. You could try and use a temp gun to verify it's actually over heating.

 

That makes, sense.. Thanks

 

So parts fiche is very vague on these switches/sensors.. My rads have a "switch" on the bottom under the fan, and a "sensor" on the clutch side, at the bottom, so I presume the temp sensor is the clutch side sensor, and the one on the fan side controls the fan?

The d-tracker manual (ya, I've got to get the S manual soon) states that there is a water temp sensor on the cylinder, but mine doesn't have that, only the two on the rads.

Am I correct?

 

Sounds correct to me.
My fan switch quit working. Checked out okay per manual in heated oil bath. Got another and it doesn't work either, so I'm assuming the switches are okay but there's a problem elsewhere. So I installed a manual override switch and turn the fan on when it's needed.

 

Put a couple temperature strips on the radiators perhaps? Not sure how accurate they read though.
I got these at McMaster Carr - McMaster-Carr