It started recently, when the car (Nissan Altima 2012) goes downhill, especially in cold weather, the temperature gauge goes down.

It can even reach the lowest point (like when the engine is completely cold).

When driving uphill, the temperature is keeping nicely and steady at about 1/3 of the scale, engine is not overheating even in warm weather.

What could cause that?

  • Ambitious-Crab-170@alien.topBEnglish
    1·
    10 months ago

    Sounds like the thermostat is stuck open, at least partially. Going downhill means the engine is under less load and isn’t generating as much heat and because it’s colder weather, dissipates heat more quickly. In warmer weather, the open thermostat allows coolant through the radiator at all times rather than when it’s supposed to at a certain temperature. This very same condition happened to me about 3 weeks ago, just in a different car. Cooled off going downhill and all.