Town & Country Van AWD V6-230 3.8L VIN L SMFI (1998)
Positive Crankcase Ventilation Valve: Description and Operation
Engine Off Or Engine Backfire - No Vapor Flow
The PCV valve contains a spring loaded plunger. This plunger meters the amount of crankcase vapors routed into combustion chamber based on
intake manifold vacuum.
When the engine is not operating, or during an engine backfire, the spring forces the plunger back against the seat. This prevents vapors from
flowing through the valve.
High Intake Manifold Vacuum - Minimal Vapor Flow
When engine is at idle or cruising, high manifold vacuum is present. At these times, manifold vacuum is able to completely compress spring and
pull plunger to top of valve. In this position, there is minimal vapor flow through the valve.
Moderate Intake Manifold Vacuum - Maximum Vapor Flow
During periods of moderate intake manifold vacuum, the plunger is only pulled part way back from the inlet. This results in maximum vapor flow
through the valve.