By Steve Martin. Republished with permission from the Summer 2016 issue of Fourteener Motoring Magazine.

Cylinder head temperature is a topic that everybody seems to have an opinion about. So how hot is too hot? Here are some rules of thumb. Based on specific configuration, your numbers may very.

Less than 275 degrees (fahrenheit) indicates that the engine is working well, but, you probably need to drive it harder. 300 to 350 degrees is considered in the optimal range for most Type IV engines. If your temperature is above 350 the cooling system may not be operating correctly. Stock engines often operate as high as 375 degrees or more, but, when the engine encounters a load, it can shoot up to 400 degrees or higher. 400 and above will damage the engine.