Car overheating (updated)

My 2001 mustang v6 has an intermittent overheating problem. I say intermittent because the car will sometimes start overheating after just 10 minutes of driving and other times can go 30 minutes and the temperature gauge stays right in the middle. Speed i’m going doesn’t seem to effect the overheating, it has begun to overheat going at highway speeds and also at slower speeds and idle. Also sometimes the car temperature gauge will show it’s running hot and then keep going up to the point where i have to pull over or else the car would overheat. And sometimes it will go up just a little past half but then go back down. And sometimes i can drive long distances and it won’t go past half at all. It’s very strange.

Also today, the temp gauge went about 3/4 up to the red zone and i pulled over and shut the engine off, then i turned the car to accessory mode within 10 seconds of pulling over, and the temperature gauge showed half. I turned on the engine again just to make sure and the gauge was back at half even though it had been at 3/4 only a few seconds ago. from what ive read this sounds like a sensor is giving false temp gauge readings, but i did a bit of research and apparently a 2001 mustang doesn’t have a coolant temperature sensor only has a cylinder head temperature sensor (idk if this is the same part with a different name) or if it does the same thing as a coolant temp sensor. What could be the issue? The car doesn’t have any coolant leaks. I’ve also replaced the thermostat and bled the system so i’m sure there’s no air trapped inside. I’m really thinking it’s a sensor, since the car overheated and then according to the temperature gauge, cooled down to normal temp within a few seconds. But which sensor would this be?


It is a cylinder head temp sensor. Coolant temp is calculated from the cylinder head temp sensor. A scan tool can access that sensor reading… on a V6, there should be 2 of them… so you can see what they are putting out. If one is failing you may get a bad coolant reading.

You also need a handheld temp sensor… an IR type works well… so you can find out the actual coolant temp by aiming it at the radiator to see if your cars gauge reading is correct or bogus.

So there are 2 cylinder head temperature sensors? Any link to a video explaining? On youtube all the videos i’ve watched only show one of them

I thought there is only one cylinder head temp sensor?

Yep, you are right, the V6 only shows one it is mounted on the backside of the drivers side cylinder head. Later model V engines have 2.

Rockauto sells the same parts under temperature sensor and cylinder head temp. There is no sensor for the gauge.