Crankcase Ventilation System Inspection/Diagnosis. GMC Truck TopKick C-Series (Conventional) C4/C5 2004

For 1990-2009 cars only

Makes 🢒 GMC_Truck 🢒 2004 🢒 TopKick C-Series (Conventional) C4/C5 🢒 Engine 🢒 Engine Mechanical - 6.6L (LB7) 🢒 Crankcase Ventilation System Inspection/Diagnosis

Concern

Action

DEFINITION: During normal operation the crankcase gases can be seen exiting from the hose at the oil separator.

The maximum crankcase pressure is 4 kPa or 16 in of water at 3,100 RPM measured at the oil level indicator tube.

Oil leak - external

•	Plugged or kinked crankcase ventilation system hoses

•	Damaged or loose crankcase ventilation system hoses

•	Valve rocker arm diaphragm covers loose

•	Oil separator oil drain hose damaged or loose

•	Too much crankcase pressure

PCV check valve (bottom of generator bracket) stuck closed

•	Valve closes when 1.47 kPa (0.213 psi) of crankcase pressure is applied from the crankcase side (bottom) of the valve.

•	Valve should allow oil to drain from the separator during idle and engine off conditions.

•	Inspect for proper operation by stopping engine and waiting 5 minutes to allow the oil to drain back into the crankcase. Remove the drain hose from the check valve. If more than residual oil (several drops) drains from the separator, replace the valve.

Restricted Positive Crankcase Ventilation vent hole inside the PCV seperator (if equipped)

Confirm the vent hole, if equipped, or area between the bracket and block is not restricted with dirt, ice, or debris.

Odors

Normal situation

Noise

Cracked hoses

Smoke

Internal engine failure