PCV Valve - Aftermarket Valve Covers

For those who want to run a PCV valve on one side of the engine, we now offer these. They are designed to fit aftermarket valve covers which use our 121-1075 grommets, which feature an inner diameter of 3/4". The barbed nipple on the top fits any standard 3/8" rubber hose, which connects to a vacuum port on the intake manifold or carburetor. Please note, these do not fit factory valve covers, only aftermarket ones. PCV stands for Positive Crankcase Ventilation. The crankcase holds your motor oil and is located at the bottom of your engine. When fuel is burned in your engine, it produces waste gases that are mostly vented out through your exhaust system. But some of these gases push their way past the pistons and into the crankcase. There, these gases can mix with motor oil to produce oil sludge, which can damage vehicle engine parts through corrosion and by clogging engine passages. If the engine is running at high speeds, these gases can also cause pressure inside the crankcase to build up. This pressure, in turn, can blow gaskets and damage seals, leading to oil leaks. The waste gases that leave the engine are comprised of about 70% unburned fuel. They used to be vented off the crankcase into the atmosphere. But starting in 1964, laws mandated that these gases be recaptured. Manufacturers began installing PCV systems, which recycled the gases into the air intake system where they could be mixed with fuel and sent to the engine to be burned. The PCV valve is a one-way valve attached to the crankcase. Waste gases exit the crankcase through the valve but cannot enter. Over time, the waste gases leave deposits on the PCV valve that can gum it up. So it needs to be replaced occasionally. This is an inexpensive part of preventive maintenance that is often overlooked, but which can have very expensive consequences. It’s good advice to keep this little valve clean and working well.