Bad Thermostat Symptoms & Fix | How to Test and Replace It FAST

Is your engine running hot or taking too long to warm up? In this video, I’ll show you how to diagnose a bad thermostat, explain the common symptoms, walk you through how a thermostat works, and show you how to test and replace it step-by-step. I replaced the thermostat on my truck and recorded the full process to help you do the same at home! 🔧 What You'll Learn: Symptoms of a bad thermostat How to test a thermostat (in or out of the vehicle) How the thermostat works in your cooling system Step-by-step replacement on my truck Tips to avoid overheating or engine damage affiliate link Coolant Vacuum Refill Kit: https://amzn.to/4lUVoJq O-Ring Silicone Lubricant: https://amzn.to/3U6dXxW