I have a 95 S10 Blazer. I have a few questions about coolant temperature.

What is normal operating temperature?
What temp should the fan turn on?

During winter (50-60 degrees) the gauge reads just under the 2nd hash mark or the quarter mark. But as soon as the outside temp gets to about 80 degrees it steadily rises on my drive home and is at the middle mark by the time I pull into my drive way. Is it normal to fluctuate like that? All my other vehicles run at the same temp whether it's freezing or 100 degrees outside.

The only time the fan is on is when I first turn the truck on for about the first quarter mile or so. Also, as soon as I turn on the A/C, the temp shoots passed the mid point within a couple of minutes and since I don't hear the fan kick in, I turn the A/C off and wait a few minutes until the temp drops and so on and so on.

Please help! I don't want to overheat the engine.

 

Normal operating temperature is around 205-210*F for a 195*F thermostat. The temperature should not fluctuate like that. It should go to the mid-point on the gauge and stay there.

The fan has its own thermostatic control that senses the heat from the radiator. As such, it does not engage in relation to the temperature of the coolant in the engine, but rather, in relation to the temperature of the coolant in the radiator. You may not hear the fan engage.

 

I agree with Kyle, the temps should not jump around like that, could be that the thermostat is sticking shut.... I had a problem where the temp would not go over 150 so mine was stuck open, I would start with that tho, they are pretty cheap and don't take long to do at all

 

I'll get to work on the thermostat first and go from there.