Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Crankcase Ventilation: Description
The closed crankcase ventilation system consist of an oil separator, an equalizer, and connecting hoses. Crankcase vapors collect in camshaft cover and are drawn into combustion chambers were they are burned.
The oil separator prevents oil from entering system along with crankcase fumes. Oil collected in oil separator returns to oil pan through a hose. Fuel evaporation system fumes are collected in camshaft cover and are purged along with crankcase fumes.
This system has 2 separate circuits, one for high speed operation and another for idle/low speed operation. During high speed operation, crankcase fumes flow through oil separator an then to air cleaner housing. From air cleaner housing, fumes are drawn through intake manifold into combustion chambers to be burned.
During idle/low speed operation, crankcase fumes flow from oil separator to equalizer. Equalizer is provided with calibrated orifices which evenly distribute crankcase vapors among all cylinders. From equalizer, crankcase fumes are drawn through intake manifold into combustion chambers to be burned.
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.