Positive Crankcase Ventilation

Your car needs to breath too

Interactive Tool

PCV Valve
This is a check valve that allows air to flow in one direction. Because of the suction created by the air being drawn into the piston chambers, the air will naturally be pulled from the crankcase past the PCV valve and meet with the oncoming air. This will most likely be after the throttle body.

Intake Manifold

KEY

Blue - Intake Air

Red - Exhaust Air

Breather Tuber
This is a check valve that allows air to flow in one direction. Because of the suction created by the air being drawn into the piston chambers, the air will naturally be pulled from the crankcase past the PCV valve and meet with the oncoming air. This will most likely be after the throttle body.

Gray - Piston Movement

Big Black - Blowby Air
            

Little Black - Crankcase Air
            

Camshaft

Camshaft

Crankcase
The oil sits in the bottom and will be pushed throughout the engine in the necessary spots by an oil pump. Also in the crankcase, blow by air will occur between the pistons and the piston walls. This air needs a blow to escape. It will find its way up the engine block and toward the PCV valve.

Exhaust Manifold

Exhaust Manifold

Piston

Piston

Flow Path

Crankshaft

Just follow the arrows and the color key to understand what is flowing where...

Oil

Various Engine Pictures

  1. engine block
  2. engine part
  3. engine block
  4. nkg spark plug
  5. valves

Piston

Piston Armature

Crankshaft

Camshaft