What Is a Distributor Cap?

Series Summary

The distributor cap is the mechanical portion of your car’s ignition system. It routes the high voltage energy of the distributor shaft’s rotating motion to the spark plugs, causing the engine’s cylinders to fire in the correct order. The distributor cap is a component that will eventually require maintenance or replacement, as it is susceptible to vibration and heat which may cause its bakelite housing to break or crack. Over time carbon deposits build and the metal terminals erode, causing distributor-cap failure. Fortunately, the distributor cap is a fairly inexpensive component and relatively easy to replace.

In this series of free how to videos our expert will take you step-by-step through the entire process of replacing a distributor cap. You’ll learn how to locate and remove the distributor cap, properly inspect it, install the new components and check your work when you’re done. You’ll become much more familiar with the mechanics of your automobile and save money in the process.

Video Transcript

"Hi! My name is Nathan McCullough. On behalf of expertvillage.com, in this clip, we’re going to be discussing what a distributor cap is. A distributor cap is the mechanical portion of the ignition system. It acts as a translator between the rotating energy of the distributor shaft and the rest of the motor. By design and function, it takes the rotating motion of the distributor shaft and translates that into appropriate timing to fire the cylinders in their firing order. It’s a maintenance item, it should be serviced or inspected at factory recommended intervals, or any other time other ignition system components are serviced for trouble, i.e. spark plugs, spark plug wires, or the ignition coil. "