An oil filled air filter or a puddle of oil in your air filter box seems like a strange happening by all means considering that its the last thing you would expect to find. Oil in the air filter or housing is known as blow-by and it can be brought about by several different factors that should be corrected immediately as it could be the result of or lead to serious engine issues. Determining the cause of the misplaced oil can be a bit tedious and will need at least one special tool that is likely available for rent at your local parts store.
Positive Crankcase Ventilation Valve
The positive crankcase ventilation or PCV valve is linked to the air intake tube through a rubber vacuum hose that uses the engines natural vacuum to keep excessive pressure build up in the engine crankcase. In most casts the PCV valve can be taken out by pulling it out of the valve cover grommet and then removing the rubber vacuum hose. Generally the PCV valve should be replaced at every tune-up, but is often overlooked. Remove the PCV valve, and into the side that rests inside the valve cover to see the check valve. Shake the PCV valve, if the check valve does not move and a rattle is not heard, the PCV could likely be the issue, allowing oil to pass through the valve and into the intake tube. Change the PCV valve and check the filter and housing after 500-1000 miles, continue on if the PCV valve is properly functioning or changing it doesn’t solve the problem.
SEE ALSO:HOW TO CLEAN AIR INTAKE FILTER
Clogged Oil Passages
Consider the car routine maintenance schedule. Engine oil that becomes excessively old and worn will keep deposits in the engine oil passages over time that can build up and cause bigger problems. As the oil passages become clogged it geta difficult for oil to drain from the top of the engine down into the crankcase, cause oil to build up and pool inside the top of the cylinder head. Extremely clogged passages will make pressure to build up and will open the opportunity for oil to push through the PCV valve and enter the air intake tube where it will drain into the air filter and filter housing. Buy an engine flush formula from your local parts store and follow the directions. In general you will pour the formula into the oil and run the engine for a period of time. Once the engine has been flushed drain the oil and refill it with fresh engine oil. Change the filter and see if the problem persists. In some cases you may need to flush the engine multiple times to thoroughly clear all the oil passages and completely solves the problem.
Worn Piston Rings
Each piston has an oil ring that allows the piston to travel up and down without oil passing the top of the piston and entering the combustion chamber. Once the oil is in the combustion chamber it will be burned off during combustion or pushed into the intake and exhaust manifolds resulting in oil coated exhaust or oil working its way to the air filter box. The classic tale sign of worn or leaking piston rings is a cloud of blue smoke when the engine starts or smoking while the engine is under high load. Worn piston rings can be seen by running a compression test on each cylinder. Take out the fuel pump fuse and the wire from the ignition coil to the distributor; unplug the ignition packs or individual coils for a distributor-less ignition. Fix a compression tester into each individual spark plug fitting. When the tester is installed have a helper crank the engine; an accurate reading will be gotten after the engine has cranked 6 times. Write down the number and repeat for each cylinder and compare them when the process is finished. Each cylinder in general should read between 140 and 160 Psi. If any cylinder tests low squirt a small amount of oil or transmission fluid into the corresponding spark plug hole and perform the test again. If the compression increases after applying oil then the piston ring for that cylinder is bad and is likely the cause of the oil blow-by.
Repairing Internal Problems
Changing a piston ring is an in-depth process that will want you to remove the engine from the vehicle and tear it down completely. Changing a piston ring will result in a full rebuild of the engine and should be given to a mechanic that has extensive internal engine experience if you are not qualified to perform such a repair. Repairing an internal engine issue such as a piston ring is time consuming and will tack on a hefty charge for labor, so if you cannot have the repair performed right away check the oil daily and change the air filter anytime it becomes saturated to help keep the engine running as smooth as possible and keep further damage until the repair can be performed.