Fix Coolant Leaks: 2021 GMC Sierra 3500 HD AT4 6.6L V8

Follow the steps in this video to see how to fix minor coolant (antifreeze) leaks in your 2021 GMC Sierra 3500 HD. Leaking coolant / antifreeze is one of the more common types of leaking fluid from Sierra 3500 HD engines. Engine coolant (which is also called antifreeze or anti-freeze) moves through the inside of your Sierra 3500 HD engine and keeps it from overheating. Coolant / antifreeze can leak from the reservoir, radiator or any hose, in 2021 Sierra 3500 HD with the 6.6 liter engine. However, a coolant leak (aka an antifreeze leak) is most likely to occur where the hoses connect to the engine or radiator. Otherwise, your Sierra 3500 HD may have a radiator leak. This video shows you where the coolant reservoir, hoses and connections on your 2021 Sierra 3500 HD AT4 are located and the steps needed to fix minor leaks.

A few things to note about coolant is that it is sweet tasting and highly toxic, so it can end up in the dog's stomach pretty quickly. If you ignore a small coolant leak long enough, you will run out of coolant, which leads to an overheated engine and other serious, but highly avoidable, problems. An anti-freeze leak can cause the temp sensor to record high engine temperatures in a 2021 GMC Sierra 3500 HD. Always protect yourself with safety glasses and gloves when working with the coolant on your Sierra 3500 HD.