
1. Overheating.

This problem can definitely be attributed to other issues with the cooling system, such as leaking hoses, but checking for a bad thermostat should be on your list as well since this is a fairly cheap, easy fix.
2. Under Heating.
If you have been driving for a few minutes and your vehicle’s temperature gauge needle is still sitting close to the bottom, it’s time to check your thermostat.
3. Temperature Fluctuations.
4. Poor Engine Performance.
If you notice any of these issues, don’t hesitate to pop open your hood and check out your car’s thermostat. A new thermostat can be purchased at your local auto parts store and the repair is an easy one that can be done yourself if you’re looking to save some money.