Replacing Your Car's Crankcase Breather

tools for a project
  • 1-2 hours
  • Beginner
  • 25-50
What You'll Need
Regular, and Philips screwdrivers
New air filter
New crankcase breather filter
New crankcase breather element (optional)
Damp cloth
Compressed air (optional)

The crankcase breather is also known as the PCV valve, or Positive Crankcase Ventilation valve. It removes harmful gasses that accumulate in the engine. A crankcase filter prevents oil-contaminated air from going back into the engine. The crankcase filter captures the oil residue before the air goes back into the engine. The crankcase breather and air filter should be replaced every time you have an engine tune-up.

Step 1 – Preparation

Crankcase breather filters are located in different locations depending on the type of vehicle you own. Before you begin, read the car owner's manual to familiarize yourself with where the crankcase breather is located. Also, follow all recommended safety precautions. Ensure that you have enough workspace before you start working on the project.

Step 2 – Removing the Old Crankcase Breather

Lift the hood of the car and locate the air filter housing cover. Loosen the fasteners that hold the cover and lift the cover out of the way. Remove the air filter and take notes of how it sits in the housing. You can take notes on paper and draw diagrams to help you remember.

Inspect the filter and if it is very dirty, throw it away. If you can blow the debris away with the can of compressed air, you can reuse the filter. Next, locate the crankcase breather element and remove it. Inspect it for oil and dirt. If the breather element is very oily or dirty, throw it away. Remove any fasteners or retaining clips holding the crankcase breather housing in place, and then remove the housing. Remove the breather from the housing and throw that away.

Step 3 – Installing the New Crankcase Breather

Clean any debris from the crankcase breather housing and install the new breather. Install the air filter housing cover. Wipe the housing clean with a damp cloth. Be sure to avoid getting any debris in the air ducting. Replace the air filter and install the air filter cover.

Tips and Warnings

Be sure the engine has been off for a while so it has cooled down when you work on it.

Avoid getting any dirt or debris into the air duct while replacing these parts.

Keep a small can of compressed air at hand while working around the car; they can be purchased at most office supply stores, hardware and automotive stores.

Use a cup or can to keep the small screws and fasteners so they are not misplaced.

Never place anything on the battery because it can react with the battery and can explode.

A cracked or damaged crankcase breather can affect the performance of your car's engine.