How to stop engine oil in an air breather

Written by cassandra tribe
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How to stop engine oil in an air breather
Learning to properly read the dipstick prevents oil in the air breather. (Stockbyte/Stockbyte/Getty Images)

The crankcase air breather is opposite the PCV valve on the engine to allow air flow to enter the positive crankcase ventilation system. This pushes gases from the engine into the PCV valve and breather hoses. The ventilation system is designed as part of the emissions control system of the vehicle and prevents gases from the engine from being released into the environment. If the air breather filter becomes clogged with oil, the system won't work. It is easy to stop engine oil in an air breather because there is only one cause for it: too much oil in the engine.

Skill level:
Moderately Easy

Things you need

  • Drain pan
  • Vehicle manual
  • Socket set
  • Strap wrench (if needed)
  • Oil filter
  • Funnel
  • Engine oil
  • Air breather filter cover
  • Flathead screwdriver
  • PCV valve
  • Rubber hose (if needed)
  • Hose clamps (if needed)

Show MoreHide


  1. 1

    Turn the engine on and let it run until it reaches operating temperature and then shut the engine off. This will warm the oil enough to make it free flowing and easier to drain.

  2. 2

    Place a drain pan under the oil drain bolt on the bottom of the oil pan. Look in the vehicle manual for the drain bolt location if it is not readily seen. Use a socket wrench to remove the bolt. Wait for all the oil to drain out and replace the bolt.

  3. 3

    Use a strap wrench or socket wrench, depending on the design, to remove the oil filter. Dip a finger in the oil remaining in the filter and wipe it on the gasket of a new oil filter. Install the new oil filter by screwing it into place by hand and then tightening it with a strap wrench or socket wrench.

  4. 4

    Remove the oil filler cap. Insert the narrow end of a funnel in the oil tube and add oil to the engine. Add enough oil to meet the requirements listed in the vehicle manual for a complete oil and filter change -- not just an oil change, as these are two different amounts of oil. Remove the funnel and replace the oil filler cap.

  5. 5

    Grab the air breather filter cover and pull it off the air breather tube. Push a new air breather filter cover down onto the breather tube.

  6. 6

    Use a flathead screwdriver to loosen the lock screw on the clamp holding the breather hose onto the positive crankcase ventilation (PCV) valve. Pull the hose of the outlet connector off the valve. Grab the valve and pull it out of the valve hole.

  7. 7

    Push a new PCV valve into the valve hole, being careful to turn the outlet connector for the breather hose in the same direction as the old valve.

  8. 8

    Inspect the breather hose for wear, cracks or pinholes. Replace the hose with a matching length of new hose, if necessary. Push the end of the hose onto the outlet connection of the PCV valve and tighten the hose clamp screw with a flathead screwdriver to secure the hose.

Tips and warnings

  • Air breather filters will discolour with use. Before assuming there is a problem with too much oil in the crankcase, touch the filter. With normal discolouration from the oil in the engine, very little will come off the filter. If the oil in the filter can discolour the skin then there is too much oil in the crankcase and it should be corrected.
  • Make sure to add the correct amount of oil needed after an oil and filter change or there will be too little oil in the engine and it will overheat and damage the engine block.

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