My temp gauge on the dash started showing the car getting hot as I sit with the car running. When I started driving it goes down. I figured the thermostat was sticking so I replaced it and now the temperature gauge is doing the same thing. I started my car after letting cool and had a heat sensor pointed at the thermostat and as the guage on the dash went into the red the engine temp never changed by more than 12 degrees. I'm hoping it is just a sensor,but which one? Also When I drove it last it became extremely hard to turn the wheel. I checked the power steering fluid and the belts/hoses and all look good. Any suggestions.

cooling fans not working

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These details will help.
Thanks.

Did you flush the radiator when you replaced thermostat too? Sounds like it's clogged and the coolant is not circulating as it should. It probably needs to be rodded out or replaced by now.
Check your cooling fans for proper operation. Make sure the outside of the radiator & condensor are clean, and not full of bugs & debris...I hope this helps.

your thermostat might be stuck open so while idle it can warm up but as soon as the motor increases speed it cools down quick

During the winter time the engine may not produce enough heat to go half way. You can modify this by installing a hotter thermostat. But I would not go more that 20 degrees F though, or you could create issues for summer driving.

Please do not drive your car until you can check a few things.

To answer your question...your car is hot while sitting at a light, but not when driving because of air movement. Think of it like like this...if you are standing in front of a fan, you feel cooler. If you step away from the fan, it will be warmer.

Back to your car troubles...you most likely are low on antifreeze. Please check the radiator for how much antifreeze you have. You will want to fill the radiator to the cap. If it has been this way for a while, you will have air in the line. After running the car for a while (after the fans turn on) add more antifreeze. It will most likely will show a lower amount.

Hope this helps.

change temp sending unit

they are designed not to fluctuate with engine temp and are kept stable once operating temp is reached. only if the temp exceeds a set mark will the needle rise to indicate overheating,

Check to make sure your thermostat works right by monitoring the warming up of your engine. With a completely cold engine, start and run the engine for a few minutes, then put your hand on the top radiator hose to monitor if and when it gets warm as the thermostat opens more and more and note the gauge reading( if it works) the top radiator hose should be unbearably hot within 5-8 minutes. If the therm. opens right it should close right aswell, staying open a little while eventhough the radiator may have cooled may be what you are experiencing causing the rapid cooling and is nothing to worry about. The Hose should not get warm very soon after starting the engine. Regarding you gauge, lets take one step at a time, verify proper op. or the therm.

head gasket does the overflow bootle have bubbles in it when idleing warm if does most likey rear head gasket.