Why is Oil Coming Out of Air Filter?

Possible reasons are as follows:

  • Oil leakage Air box is not sealed well
  • Worn out Air Chamber Gasket
  • Faulty air filter o-ring
  • Leaking PCV valve
  • Loose O-Ring or Clamp on Airbox

Oil leakage Air box is not sealed well.

So, you’ve got oil coming from your air filter.

Here are three things to check:

  • Check to make sure the o-ring is not damaged or missing.
  • Check to make sure the o-ring is seated properly in the groove of the bottom of the top fender.
  • If those two things check out, you may have a cracked or damaged air box or there could be dirt and debris in the air box that needs to be cleaned out with some compressed air or a shop vac

Worn out Air Chamber Gasket.

The air chamber gasket is the seal between the engine block and the cylinder head, where an inner and outer metal ring are sandwiched together by a rubber gasket inside. A worn out air chamber gasket can cause oil to leak into the combustion chambers. This can cause smoke coming from tailpipe or make your oil levels low if it’s bad enough. This can cause a misfire in your car because of the oil on plugs and cylinders. The best way to check for this is to pop off your air filter box, take off your air filter and look for any oil residue in there or just on top of your engine around that area. If you suspect this is your problem then replacing it should not be too hard if you have basic mechanical skills.

Faulty air filter o-ring.

One of the most common causes of oil coming out of the air filter is a faulty air filter o-ring. I’m going to describe an example of this and how to fix it.

Let’s say you’ve been riding your motorcycle for a while and have noticed that there is oil on the bottom side of your air filter. You might clean off the air filter, put it back in place, tighten the cover, leave your bike on its side stand for 10 minutes or so, move it upright and check under the air filter again—only to find that more oil has leaked through the air filter. If this happens, chances are you have a faulty air filter o-ring.[1]

Replacement o-rings are readily available from your local motorcycle shop or online.[2] Once you’ve obtained one, changing it out for a new one should be straightforward: simply loosen up the bolts holding in your gas tank (or whatever covers/holds in your old o-ring), remove the old o-ring and put in a new one. Finally, put everything back together and continue riding!

Leaking PCV valve.

If you’re wondering why oil is leaking from your air filter, then there are a few reasons that could be happening. One common reason for this kind of leak is the PCV valve —also known as the Positive Crankcase Ventilation (PCV) valve— becoming stuck open or blocked.

The PCV valve is a one-way check valve that allows blow-by gases to escape the crankcase. Blow-by is caused by combustion gases getting past worn piston rings or valve guides, resulting in pressure buildup and oil leaks if not properly vented. If it’s stuck open, then oil vapors will escape through the intake manifold, where they may coat other components with excess oil and negatively affect engine performance. It can also cause sludge buildup on the engine block itself and prevent proper ventilation of crankcase gases, which can lead to more serious issues down the road.

If your air filter has an oily coating on it, then make sure to replace it right away—this can clog up your air filter quickly and reduce airflow into your vehicle’s engine. Finally, if your car has an oil separator behind its intake manifold (sometimes called an ‘oil catch can’), then you may need to look at replacing it since these filters tend to clog over time due to excessive blow-by gas buildup caused by dirty PCVs or failed intake valves/gaskets on newer engines with direct injection technology (which does not allow any fuel into the cylinder head).

Loose O-Ring or Clamp on Airbox.

In the case of an o-ring, it is used to maintain a tight seal between the airbox and the carburetor. If this o-ring is damaged or stretched out over time, oil gets into the mix and prevents proper sealing, which allows oil to leak from the carburetor.

In order to fix this issue, you will need a new o-ring and a little bit of elbow grease. Simply remove any fairings or panels that are blocking access to your airbox. Once they have been removed, you should be able to see the airbox attached to your motor with two clamps holding it in place. Remove these clamps and slide off your airbox and pull back on your throttle body boot (rubber hose) in order for the whole assembly to come off as one unit (this will make it easier for you). Once everything has been removed from your bike, check for any damage. If there is one present, replace it immediately! Once you have inspected your entire unit for damage, grab your new o-ring that comes included with most kits! Slide this new piece onto where it needs to go (the hole on top) then put everything back together in reverse order as how you took them apart!

Your bike´s oil coming out of the air filter might be caused by some specific issues.

The oil coming out of the air filter could be caused by various issues. The following are some of the most common reasons:

  • Oil Leakage Air Box is Not Sealed Well

When an oil leakage from the air filter accompanies a puddle of oil, it could mean that your bike´s seals or gasket in the valve cover are worn out and loose. You should look for significant gaps between the valve cover and its mating surfaces on your bike´s head. If there is any gap, you need to replace those gaskets or seals because they might not be doing their job well enough.

  • Worn Out Air Chamber Gasket

Your bike´s air chamber gasket is what makes sure that all the vacuum in its crankcase vents back to its air box through its PCV valve. If this does not happen, any vacuum created during combustion will suck engine oil through your bike´s seals and gaskets at every point where there is a passage to its crankcase gases, i.e., where there are breather tubes from your bike’s gearbox, clutch cover or camshaft covers (if equipped). In this case, you need to replace these worn-out gaskets with new ones so that you can seal them properly.

  • Faulty Air Filter O-ring

If the air filter o-ring wears out because it has been used for a long time or if it was made of low quality material in the first place, then getting a new one will solve this problem completely as it would prevent air leakage and thus any possibility of an engine malfunctioning because of low pressure on one side while high pressure exists on another side as well as preventing leakages that can lead to other problems like overheating due to loss of coolant via cracks within metal parts housing fluids such as those found inside radiators which could cause damage due to overheating if they aren’t replaced quickly enough so

Steven Hatman
Steven Hatman

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