The 6.7 Cummins crankcase filter removes moisture and contaminants from the air that enters your engine's crankcase

The 6.7 Cummins diesel engine uses a crankcase ventilation system that pulls air through the crankcase to manage pressure and gases. The crankcase filter — also called a crankcase breather filter — sits in this ventilation line and traps water vapor, oil mist, and particles before they can damage the engine or escape into the atmosphere. Without it, moisture would accumulate inside the crankcase, thinning your oil and causing corrosion.

This filter is separate from your engine oil filter. It serves a different purpose and requires its own maintenance schedule. On the 6.7 Cummins, the crankcase filter is located on top of the engine and is straightforward to inspect and replace yourself if you have basic tools.

Key Takeaways

  • The 6.7 Cummins crankcase filter prevents moisture and oil mist from entering the engine by filtering air in the crankcase ventilation system.
  • Dodge recommends inspecting the crankcase filter during each oil change and replacing it every 15,000 to 30,000 miles, depending on driving conditions.
  • A clogged crankcase filter can cause excessive crankcase pressure, leading to oil leaks from seals and gaskets throughout the engine.
  • You can replace the crankcase filter yourself with a socket wrench and the correct replacement filter part number for your model year.
  • The crankcase filter is not the same as the engine oil filter and does not need to be replaced at every oil change.

Where the crankcase filter sits and what it looks like

On the 6.7 Cummins, the crankcase filter is mounted on top of the valve cover, toward the rear of the engine. It is a cylindrical canister, typically black or gray, about 3 to 4 inches tall and 2 inches in diameter. The filter screws into a threaded housing on the valve cover.

The filter has a rubber seal at the base and a threaded cap at the top. When you look at the engine from above, you will see it clearly — it does not hide under other components. This location makes it one of the easier filters to reach on the 6.7 Cummins, even in a truck bed or engine bay with limited space.

When to replace the 6.7 Cummins crankcase filter

Dodge's maintenance schedule recommends inspecting the crankcase filter at every oil change. If you drive in severe conditions — towing, dusty environments, or frequent idling — inspect it more often. Replace the filter every 15,000 to 30,000 miles, depending on how much moisture and dust your engine encounters.

Signs that your crankcase filter needs replacement include visible dirt or oil coating on the outside, a strong smell of unburned fuel near the engine, or oil leaking from valve cover gaskets and crankcase seals. A clogged filter forces the crankcase ventilation system to work harder, raising pressure inside the crankcase and pushing oil past seals that were designed for normal pressure. If you notice oil seeping around the valve covers or oil pan gasket, a plugged crankcase filter is often the culprit.

How to replace the crankcase filter yourself

You will need a socket wrench (usually 1 1/16 inch or 27 mm, depending on your model year), a new crankcase filter, and a clean rag. The job takes about 10 to 15 minutes.

First, locate the filter on top of the valve cover. Unscrew the filter by turning it counterclockwise by hand or with the socket wrench if it is tight. As you unscrew it, have the rag ready — a small amount of oil may drip from the seal. Once the old filter is off, wipe the threaded housing clean with the rag to remove any dirt or old oil residue.

Take the new filter and explore a thin layer of fresh engine oil to the rubber seal at its base. This helps create a watertight seal when you install it. Screw the new filter into the housing by hand until the seal contacts the surface, then tighten it an additional three-quarter turn with the socket wrench. Do not over-tighten — you only need enough pressure to compress the seal.

Crankcase filter part numbers for different model years

The crankcase filter part number varies slightly by model year and engine configuration. For most 6.7 Cummins engines in Dodge Ram trucks (2007 and later), the OEM part number is 68197867AA or 68197867AB. Some model years use 68197867AC. Always verify the correct part number for your specific truck year before ordering, as using the wrong filter can result in a poor seal or fit.

You can find the correct part number by checking your owner's manual, calling a Dodge dealer with your vehicle identification number (VIN), or searching online parts catalogs with your truck's year, make, and model. Aftermarket filters are also available from suppliers like Napa, AutoZone, and Amazon, often at a lower cost than OEM parts. Verify that any aftermarket filter is designed specifically for the 6.7 Cummins and has the same thread size and seal diameter as the original.

What happens if you ignore a clogged crankcase filter

A clogged crankcase filter restricts airflow through the crankcase ventilation system, causing pressure to build up inside the engine. This excess pressure forces oil past seals and gaskets that are designed to hold back oil under normal conditions. You will see oil leaking from the valve cover gaskets, the oil pan gasket, the rear main seal, and sometimes even the turbocharger seals.

Over time, a pressurized crankcase also forces oil into the intake system, where it can foul the air filter and reduce engine performance. In severe cases, oil can enter the combustion chamber, causing excessive smoking and carbon buildup. Replacing the crankcase filter before it becomes completely clogged prevents these problems and keeps your engine running cleanly.

Crankcase filter versus engine oil filter

These are two different filters that serve different purposes. The engine oil filter cleans the oil that circulates through the engine and is replaced every 5,000 to 10,000 miles (or as recommended in your maintenance schedule). The crankcase filter cleans the air that enters the crankcase ventilation system and is replaced every 15,000 to 30,000 miles.

The oil filter is under pressure and contains oil. The crankcase filter is not under pressure and contains only air and moisture. They are located in different places on the engine and require different replacement procedures. When you change your oil, you replace the oil filter. When you inspect your crankcase filter, you check whether it needs replacement based on its condition, not on a fixed mileage interval.

Frequently Asked Questions

Can I drive with a clogged crankcase filter?

You can drive short distances, but you should not ignore it. A clogged filter causes crankcase pressure to rise, which leads to oil leaks. The longer you wait, the more oil you will lose and the greater the risk of engine damage. Replace it as soon as you notice the filter is dirty or if you see oil leaking from gaskets.

How do I know if my crankcase filter is clogged?

Inspect it visually during an oil change. A clean filter is light gray or tan. A clogged filter is dark brown or black and may have a thick coating of oil and dirt. If you cannot see through the filter material when you hold it up to light, it needs replacement. You may also notice oil leaking from valve cover gaskets or a strong fuel smell near the engine.

Is the crankcase filter the same as the PCV valve?

No. The PCV (positive crankcase ventilation) valve is a separate component that regulates crankcase pressure and directs gases back into the intake manifold. The crankcase filter cleans the air entering the crankcase. Some 6.7 Cummins engines have both, and both may need inspection or replacement at different intervals.

What if I use the wrong crankcase filter part number?

Using the wrong part number can result in a poor seal, allowing unfiltered air into the crankcase or causing the filter to fall off during operation. Always verify the correct part number for your model year before installation. If you are unsure, contact a Dodge dealer or check your owner's manual.

Do I need to replace the crankcase filter every time I change my oil?

No. Inspect it at every oil change, but replace it only when it is visibly dirty or every 15,000 to 30,000 miles, whichever comes first. Replacing it more often than necessary wastes money. Replacing it less often than necessary risks engine damage from excess crankcase pressure.