I drive a 97 Honda Civic Lxi. My normal engine temp is about midway through the temp dial.

However, I recently noticed that whenever I drive at NLEX and go above 100kph (around 2,800 rpm), the engine temp starts to rise rapidly. When I reduce speed to around 90kph, the temp needle returns to the normal level.

I don't experience this when driving around the city or driving a low speeds. I've not attemped to push it for fear of overheating the engine. When I check the water level at my destnation, everything is normal. There are no leaks in he radiator or the hoses.

Any idea why this is happening?

Thanks.