DESCRIPTION
Isuzu uses a closed type system which is designed to draw blow-by gases into the combustion chambers for reburning. Gasoline models use a baffle plate in the valve cover, regulating orifice, and connecting hoses to air cleaner and intake manifold.
Diesel models use a PCV valve assembly (containing PCV valve and oil separator), oil drain hose, and check valve.
Crankcase Ventilation System (Except Impulse & P'UP Diesel) Gasoline engine system is shown. Scheme 1
OPERATION
On gasoline models, blow-by gases and fuel vapors are mixed with air from air cleaner. Oil particles are separated by the baffle plate and gases are then drawn through regulating orifice. When engine is running at wide open throttle, intake manifold vacuum is not high enough to recover all gases and part of the gases are drawn into air cleaner.
On diesel models, a diaphragm-type PCV valve controls valve cover pressure. When valve cover and intake manifold pressure difference reaches a specific value, PCV valve opens and allows blow-by gases to mix with intake air.
Crankcase Ventilation System (Impulse). Scheme 2
MAINTENANCE
Every 12 months or 15,000 miles, clean internal part of hoses and regulating orifice in detergent oil and blow away foreign matter with compressed air. Check all passages and hoses for obstructions and deterioration. Clean contamination from inside of baffle plate.
On diesel models, check PCV diaphragm for damage and sticking to seat, check oil separator element for wear (if equipped), and check one-way operation of check valve (if equipped). Flow direction should be from PCV valve assembly through check valve to oil pan. Flow in the opposite direction should be blocked.
Crankcase Ventilation System (P'UP - Diesel) Turbo Model Similar. Scheme 3
SYSTEM TESTING
Note. Testing information is not available.