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Oil Fouled Air Cleaner

Q. I'm elated that you are willing to read... and hopefully respond to my question. I am the original owner of a 1989 Plymouth Grand Voyager, 3.0 Liter (Mitsubishi) V-6, automatic (4 Speed with lock up), and 104,000 miles racked up. The vehicle has been well maintained, and still looks and runs like new. Other than scheduled maintenance, the only repair done to this vehicle has been a new starter (99,000 miles), and brake pads/shoes (96,000 miles).

The engine has always used just a little oil... until recently when consumption has increased to about 1 quart every 3,000 miles. I attribute some oil consumption to normal wear... but have discovered an inordinate amount of oil in the breather portion of the air cleaner box, coming up from the valve cover breather tube. I replaced the PCV valve, air cleaner internal sponge stuff and air cleaner... several times. The problem continues to return, again fouling the new air cleaner and internal air cleaner box sponge stuff.

I am at a loss, and most sincerely look forward to your thoughts and recommendation!! THANK YOU!

Best Regards,
Bob

A. First thing I want to say Bob is I answer ALL my readers questions. I don't pick and choose the easy ones. If I don't know the answer to a question, I will find it for you. Sometimes it's difficult to answer all questions in a timely manner, but I do the best I can.

You're in the ball park, but you need to look at the other end of the system for the problem. The breather element (the internal sponge stuff) is the "air filter" for the Positive Crankcase Ventilation (PCV) system. What it does is this; a vacuum line goes from the intake manifold to the engine block on one end. On the other end a hose goes from the air cleaner, to the PCV valve which usually sits in a rubber grommet on the valve cover. This creates an air flow through the crankcase which draws all the blow by gases into the intake manifold to be recirculated through the engine.

Nine times out of ten what happens is that the vacuum hose to the manifold gets soft and collapses, cutting off the vacuum. What you need to do is look at the hose and be sure it is not collapsed or cracked. This is what causes the oil to back up into the air cleaner.

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