Oil in the Air Filter

Oil in the Air Filter

Having oil in the air filter usually is caused by a bad PCV valve (Positive Crankcase Ventilation Valve) and can be fixed by simply replacing the valve.

To check to see if you have a bad PCV valve, remove the valve from the rubber grommet in the valve cover and place your thumb over the valve with the engine idling at normal operating temperature.

You should be able to feel a vacuum. If no vacuum is felt, turn the engine off and shake the PCV valve and listen for a rattle. If you don’t hear a rattle, replace the PCV valve with a new one.

While it’s not uncommon to have a small amount of oil in the air filter, excess oil could mean bigger problems than just a bad PCV valve.

As engines get older and start to ware you will get what is called “blow-by” this is caused by worn rings that allow excess pressure to build up in the crankcase and will force oil past the PCV valve and into your air filter.

If this is what’s causing your oil in the air filter, you may be looking at having to rebuild your engine.

It would be wise to take your Jeep to a qualified mechanic to have your engine compression tested to see if you are starting to have ring or valve problems.

About the author

Matthew Brodie

Hi there! This blog was created to share my off-roading, gear-related knowledge with those interested in the field. I’ve worked as mechanic for years and have been a devoted off-roader for as long. Now, I’ve decided to combine the two and share my experience with passionate audience. I do not claim to know it all – but when something new hits the surface, I will be on it to research its ups and downs. Call me an off-roading nerd if you like, and as long as you can find something useful in here – you are heartedly welcome!

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