Recently, I discovered I had a nasty problem in my car. It was a problem I had known about and expected to either not be too serious, or manageable in the long run. By design, the Mazda 6 with the 3.0 Ford V6 engine has a fairly sub standard positive crankcase ventilation system (PCV). A crankcase is sealed, but all types of things you don’t want accumulating will build up inside, such as unburned fuel, fuel vapor, oil vapor, moisture, etc, and need somewhere to go. The job of the PCV valve is to provide an outlet for this stuff to escape, either directly to the atmosphere, or to your intake manifold so that it can be re-burned, either way preventing sludge pate from forming in your engine.
The PCV system on the 3.0 Ford V6 does not work. Well, let me rephrase that, it works for a few thousand miles, and once the car starts aging, will fail every few thousand miles, to the point where owners either replace them and pay roughly $25 for one each time, rig up their own system with dual PCV valves, or just eliminate it all together. The major problem is the oil consumption. Upon my last oil change, 6 quarts had gone in previously, and only 3 quarts came back out. The reason is in part due to the give it the beans system our cars have. At a certain rpm, a flap in our intake box (factory intake) and the computer says its go baby go time based on crankcase and oil pressure (from vacuum). I have the flap deleted and my air box is completely unrestricted, because like many owners, we like go baby go time to be all the time.
Except sometimes, when you really make it go baby go time during spirited driving, your PCV fails so bad that the pressure in your crankcase builds up enough to pop your dipstick out. I realized why some owners on my car’s forum had decided to just eliminate the thing and run oil catch cans, collecting the large amounts of oil instead of burning it off and adding oil every so often. So I searched, and searched, and searched, and you’ll have to read part two of this series to see what happens.