Engine temperature light

[Steve port 1]

Hi my engine temperature light came on whilst I was doing some slow riding training (tight circles figure of eights). It went out as soon as I pulled away. It was a sunny day at 15 degrees Celsius. The fan works and there is water in the expansion bottle. I've never noticed it before, had any else had this happen ? . Thanks.

[jeremyr62 2,557]

Not on an NC, but slow riding will really test an engine. I had overheating issues with a FJR doing a slow riding course but these never recurred in normal riding. I wouldn't worry.

[Defender 3,837]

No, never in all my 11+ years of ownership have I seen that, but I have had the cooling fan come on many times.

[Defender 3,837]

My NC'X has run the cooling fan on quite a few occasions over the 11+ years I've owned it and my much newer 450cc single does that a bit more often, but then it has a smaller radiator and less coolant in the system, so I think that's only to be expected, but I've never seen the coolant warning light come on, so far!

[Steve Case 954]

Forget the expansion tank is there water in the radiator? Thats the most likely cause of an engine temp warning.

[Tegraman 743]

6 hours ago, Steve Case said:

Forget the expansion tank is there water in the radiator?

Indeed. NCs and most others don’t self-bleed their coolant circuit because the header tank is below the rad. Doesn’t matter normally, but it pays to check for trapped gas in the rad from time to time. I think that antifreeze is toxic to algal life so gas shouldn’t accumulate over time. Old, weak, antifreeze, maybe.

[Steve Case 954]

Its the old french conundrum where psa cars used to run hot as they would blow off coolant.

1st they didnt have expansion tanks so they used to dump over the alternator and steering pump and then after expansion tanks were fitted the system leaked. And guess what.