Join Date: Aug 2007
Location: Staunton, VA - USA
I'd suspect the sensor is going bad, but, you need to be certain you're not having localized overheating (unlikely, but possible).
I imagine that there is one temperature sender for the gauge and another for the warning light, but I don't know this for certain and don't have the technical documentation to confirm it.
You should check with an IR thermometer in the region of the temperature sender for the warning light when it comes on to determine whether localized overheating may be occurring. This can happen if the coolant has not been changed regularly and one of the passages for coolant has suffered corrosion collecting on the inner surface, reducing the ability to transfer heat to the coolant.
The opposite of a correct statement is a false statement. But the opposite of a profound truth may well be another profound truth. ~ Niels Bohr