After reading a lot about these engine covers on social media I finally decided to give them a try. Some say they can reduce ventilation in engines, causing them to overheat. However, I did my own testing with a heat gun and measured the temperature of motors with and without covers. Not only do these caps keep dirt and grit out, but they also act as heat sinks, pulling heat away from the motors and lowering the internal temperature. So, good buy. Five stars.