temperature/thermostat problem?

[kudkudniyog]

Hello all,

When my car is on the highway (60-80 mph), the temp gauge goes all the way down to "C". Then when I exit and drive around it rises to half between C & H. When I go back on the highway, the temp gauge goes back all the way down to "C".

I am thinking it might be a possible thermostat that is stuck open. Any 2nd opinion?

[Nd4SpdSe]

I agree.