Step 1: Pop open the hood and look for the crankcase breather. The breather’s location is dependent on the car make and model, so the car’s user manual is a good reference.
Step 2: Once you’ve found the crankcase breather in your vehicle, loosen the fasteners of the filter housing cover and lift out the cover and the air filter itself. Check the condition of the filter; it it’s completely dirty, replace it with a new one. If it’s fairly in good condition, clean it using a can of compressed air.
Step 3: Remove the crankcase breather element. If it is too oily and dirty, it will have to be replaced as well.
Step 4: Remove the fasteners or retaining clips that hold the crankcase breather housing in place and lift the housing out. Once the housing is free, detach the breather itself.
Step 5: Clean any accumulated debris on the crankcase breather housing and install the new breather.
Step 6: Clean the filter housing cover with a damp cloth. Replace the filter housing cover and the air filter.
Step 7: With all the components back in their places, close the hood and test drive your car.