So on my 1996 S10 4.3, 4x4, when I first start driving it. say in the morning, as the engine warms up, the temp gauge goes up to around the middle, and then goes down to normal, and keeps fluctuating a bit until finally it stays at the normal position as I keep driving. I'm wondering if the thermostat is bad, or maybe the temp sending unit is bad? Any ideas?

Thanks.

 

The normal operating temp is 195° F. Which is almost the middle of the guage. If the coolant is full I would change the thermostat, it may be sticking.
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