sort of tearing into the pcv valve, control valve for emission control, or whatever the bloody thing is called and looking for the "goo" or simply relying on a decrease in mileage, how do you know if you need to replace your pcv unit?
If you can measure the vacuum level in the crankcase, it should be between 3 to 4.5" of water column if I remember correctly.
If the CCV isn't working properly you could have much higher vacuum level which can suck oil out of the engine.
Most DIY guys don't have a manometer, you can make one, just google "manometer"
Get another oil cap, drill a hole in it and screw a "1/8" NPT to hose barb" fitting into the hole. Or get a big rubber stopper that will cover the oil fill hole and put the fitting in it.
Connect the hose barb to the manometer and measure the vacuum in the crankcase.
A quick, and rather good, test is to place you palm over the oil fill hole while the engine is idling. You should feel a very slight vacuum. If it REALLY sucks on your hand, chances are good that the diaphragm in the valve has failed.
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