Temperature Gauge Dropping While Driving

[pphan3]

My car recently had smoke coming from the hood when I parked my car. When I opened my hood, I noticed coolant was splattered on my valve cover and some bubbling of coolant coming from my upper radiator hose clamp.

After replacing the upper radiator hose, I did a 5 mile drive around the area which seems to have resolved the coolant leak issue. Something that seemed odd was that when I started the car, the radiator fan turned on right away on a cold motor. While driving, I also noticed the temperature gauge was initially in the middle, but then dropped to the very bottom while driving. No engine lights appear on the dash and the engine seems to idle normally.

Does the temperature gauge dropping while driving and and the radiator fan turning on when starting the car indicate I have a bad temperature sensor and possibly a bad radiator and/or thermostat?

 

[Gunkk]

100% fan is typical of a failure somewhere in the coolant temp sensing circuit (which is sensor AND connectors AND wiring). The fail-safe is to run the fan full blast. So yes: "Probably and possibly and/or possibly" to answer the questions.

If it was not well-bled after the hose replacement, any air in the loop will not do you any favors while troubleshooting cooling system performance. So make sure that is in order.

 

[pphan3]

100% fan is typical of a failure somewhere in the coolant temp sensing circuit (which is sensor AND connectors AND wiring). The fail-safe is to run the fan full blast. So yes: "Probably and possibly and/or possibly" to answer the questions.

If it was not well-bled after the hose replacement, any air in the loop will not do you any favors while troubleshooting cooling system performance. So make sure that is in order.

Thanks Man. I ran the code scanner and came up with a faulty temperature sensor code despite no check engine light appearing. I will try and replace the sensor this weekend and burp any air in the system.