Members here might recall my numerous heating issue related posts. It was like mosquito menace, no matter which repellant, you use, they'll come back after a while.
I had almost learned to live with it, what with the dreaded message flashing everyday. I'd see the message, then feel the fan blowing hot air on my legs and keep on riding waiting for the bars to come down back to the normal region.
I had been complaining to the svc for it but they were least receptive, because this issue won't ever present itself in the svc ever. It was like the ailment refuses to manifest itself in the form of symptoms just when the doctor arrives
Read up a lot on the net and was convinced that the bike was running lean(which leads to higher engine temp), may be due to the fi system(mainly fuel pump/injector) being clogged with fuel dirt which would result in less fuel injected meaning a lean mixture.
I had even gotten the fuel pump pressure checked to rule out lower pressure, but the reading was perfectly normal. Had my spark plug changed fearing a faulty spark might also lead to this condition.
It's all there on this thread!! I had almost given up and had decided to live with it and not loose sleep and simply get the piston block/entire engine block changed whenever the inevitable seizure happens. After all, like all KTM parts, they do not cost a limb!

These were the symptoms/observations :
1) There was never a coolant overspill from the reservoir, which normally happens in these case. I had never seen a green tinge on my radiator cover or anywhere on the bike. May be it'll simply explode one day I thought

2) On the numerous svc visits, the fan would religiously turn on at 96 C and turn off at 89 C. It sometimes took more than 10 minutes to shut down in this process though.(I'll come back to this later)

3) The bike would normally be 1 bar less than the max normal even when riding at 100kmph and very rarely at 2 bar less.

4) Even when the fan turns on and then shuts off, the temp bar would be at the max normal region or 1 bar less and after 1-2 minutes the bike would again start showing "high coolant temperature" and this time the fan would many times won't even start. This led me to believe that the temp sensor had developed a fault or/and the fan motor is faulty or has grown weak.

5) This one is strange: The display would have sudden appearance of 1-2 extra bars as soon as I entered my office parking. I was perplexed and later ascribed it to the parking being a closed area with no wind assistance for the radiator at low speeds of 10kph

6) There were no other/strange noises from the engine when the "high coolant temp" message was displayed or a sudden drop in performance was noticed, though at times I could feel the pickup dropping a bit, may be mental only.

Went to the SVC last weekend after taking an appointment as the issue persisted even after the advised coolant replacement by the KTM engineer.
I had demonstrated this issue to the head mech Rehman when I had my tyres replaced 3 weeks back. This was the one time when I could reproduce the issue. So I had at least confidence that I won't be laughed at when I present my case.


After a bit of testing, we realized that everything was fine with the bike ecu/sensors, since the diagnostic tool showed the fan to kick off at exactly 96C and bring the temp down to 89C. Just that the display would see a sudden spurt in the temp with rapid appearance of temp bars when ever the headlamp was turned on!! and sudden dip when it was turned off.
Rehman it seems had an idea about the problem.He quickly cut the wiring harness to check any loose/torn wires. Logic was that some wiring may be loose and the display(or the ecu module which reads the temp signal and calibrates the bars in the display) was being fed extra voltage from the loose/torn wires carrying the headlamp. Turned out the wires were all right.
He then tightened the bolt which he told me was the earthing point for the electricals (I think the chassis is used as the ground). He then proceeded to tighten some other bigger bolts/nuts which are rarely touched at the svc on a normal service. This would have a more taut chassis meaning a better connected continuous surface for grounding and also less vibrations!!!

And voila, no more "high coolant temperature"

So the issue was basically a false alarm because of loose connection/faulty earthing.

Now that I have the benefit of hindsight, I can say symptom number 5 was because I would turn on the low beam or the pilot lamp on entering the parking lot.
In fact I don't remember encountering this issue in daytime. I'd normally have the high temp message displayed in dusk(when pilot lamp is on) or at night with headlamp on.

Regarding symptom number 2, I'd ascribe the fan keeping on running for 10 minutes to be actually because of coolant performance degradation and the replacement certainly has had benefit. The fan turns off relatively fast.Most internet sources would recommend a coolant change every 12/15 months anyway.

So guys, all the more reason for you to insist on getting the nuts/bolts tightened at the svc preferably with a torque wrench as per the correct torque. A taut chassis is a delight to ride on in any case and all the more important as it's part of the electricals!!

PS :Got my paid service(not sure which number) done and the bike is now delight to ride with new rubbers, oil, filters