Crankcase Ventilation System

WARNING: This page is about a different car, the 2021 Ford F-150. However, it is still accessible from the selected car via links, so may be relevant.

Crankcase Ventilation

The crankcase ventilation provides a means of routing and separating the oil from the crankcase gases. The crankcase ventilation system purges crankcase gases to the intake manifold.

The crankcase ventilation system consists of:

An expansion chamber separator
An oil collection chamber
A pressure regulating valve
A crankcase ventilation heater

Combustion blowby gases enter the rear port of the crankcase vent assembly and pass into an expansion chamber where the larger oil droplets fall out of the blowby gases due to a rapid decrease in flow velocity. The remaining blowby gases flow through into the cyclonic oil separator unit. The blowby gases are then separated into smaller cyclone oil separators which force the smaller oil droplets to the side walls so they drain out and flow to the oil collection chamber. The remaining lighter gases flow to the intake manifold.

There is an integrated pressure regulating valve which prevents excessive vacuum levels from being applied to the crankcase. Maintenance is not required and the crankcase ventilation is integral to the valve cover

Crankcase Ventilation Monitor

The crankcase ventilation monitor is an on board strategy designed to detect leaks in the crankcase ventilation system. The monitor can detect concerns with the crankcase ventilation system such as:

disconnected crankcase ventilation hose
disconnected crankcase ventilation sensor
large air leak in the intake air system
cracked or disconnected crankcase ventilation oil separator unit

If the difference between the desired mass air flow and the actual mass air flow is greater than a calibrated threshold a DTC may set.