Vehicle overheating I added coolant. Thermostat is stuck?

We should do two things to check this. First we need pressure test the system to make sure there are no leaks. Here is a guide that will show how to do this.

https://www.2carpros.com/articles/radiator-pressure-test

The next thing we need to do is use a laser temp gauge to find out if we have higher temp before the thermostat then after. If you do then the thermostat is stuck closed and it does need to be replaced.

https://www.2carpros.com/articles/how-to-use-an-infrared-temperature-meter

If this is what you find then here is a guide that will help with this.

https://www.2carpros.com/articles/replace-thermostat

I would not let this go because the engine is going to continue to overheat and eventually it will cause a head gasket issue or worse.

So let us know what you find with this and we can go from there. Thanks