Cam Plugs: Everything You Need to Know

If you notice oil leaking from your vehicle's engine, try not to panic. Oil leaks can have many different causes. In a worst case scenario, your vehicle may have a cracked engine block. Alternatively, it could have something as simple as a worn cam plug. Cam plugs can wear down over time to the point where they no longer contain engine oil.

What Is a Cam Plug?

A cam plug is a type of seal that's designed to prevent oil from leaking out of the engine. It typically consists of a disc-shaped piece of polymer material. Automakers will insert a cam plug into the side of their vehicles' engines.

Automotive engines leverage a camshaft to open and close the valves. The camshaft will rotate with the crankshaft to control the valves. By doing so, fresh air will enter the combustion chamber so that it can be burned with gas, and exhaust gases will leave the combustion chamber via the exhaust system.

Why Cam Plugs Leak

Cam plugs can leak due to regular wear and tear. Most cam plugs are made of plastic or a similar polymer material. While durable, they will degrade over time. Eventually, a cam plug may no longer provide an air-tight seal. As oil flows through your vehicle's engine, some of it may leak out of the sides of the worn cam plug.

Engines create both heat and pressure inside of the combustion chamber. Cam plugs are designed to resist these elements, but heat and pressure can take a toll on them. The sides of a cam plug may warp, resulting in small gaps that allow oil to leak out of the engine.

How to Diagnose and Fix a Leaking Cam Plug

To determine whether or not a worn cam plug is responsible for your vehicle's oil leak, you'll need to check this seal. Pop your vehicle's hood and look at the side of the engine for the cam plug. Assuming your vehicle has a cam plug -- not all vehicles have them -- you should find it near the bottom side of the engine.

A leaking cam plug will have signs of oil around it. You may notice oil dripping down from the bottom of the cam plug. Alternatively, there may be an oily residue around the cam plug.

You can fix a leaky cam plug by removing it and replacing it with a new one. Just remember to use an Original Equipment Manufacturer (OEM) cam plug while following the instructions in your owner's manual.