In the maintenance and repair of heavy equipment, you may usually pay more attention to the main parts with obvious faults, such as hydraulic components, engines, transmissions, etc., and often overlook the minor parts. Sometimes they are the focus you need to pay attention to. Today, we are going to discuss two important parts, the radiator cap and the coolant cap. They look similar at first glance and many people use them interchangeably, but they are not always the same concept. They are sometimes completely different things in different cooling system designs. If you are confused about the difference between the two when repairing, like me, then this article will help you to understand the difference and function of the two and the importance of using the cap correctly, so that you will no longer be confused when repairing or replacing parts.