DESCRIPTION
Honda uses a closed system to prevent blow-by gases from escaping into the atmosphere. System components include a blow-by filter (located in air cleaner), breather chamber, PCV valve, and connecting hoses. The PCV valve is located in valve cover on Accord, and in breather chamber on Civic and Prelude.
OPERATION
When engine is running at idle, high intake manifold vacuum pulls blow-by gases out of crankcase through PCV valve and into intake manifold where they mix with incoming air/fuel mixture. Fresh air enters crankcase from hose to valve cover on Civic and Prelude, and from hose to breather chamber on Accord.
When engine is running at wide open throttle, manifold vacuum at PCV valve decreases and vacuum in air cleaner increases. As a result a small amount of blow-by gas flows out of the crankcase and into air cleaner.
Crankcase Ventilation System (Accord - Except SEi Models). Scheme 3
Crankcase Ventilation System (Accord SEi). Scheme 4
Crankcase Ventilation System (Civic - Except CRX). Scheme 5
Crankcase Ventilation System (Civic CRX). Scheme 6
Crankcase Ventilation System (Prelude). Scheme 7
MAINTENANCE
Service crankcase ventilation system every 60,000 miles or 4 years on Federal models, and every 30,000 miles or 2 years on California models.
SYSTEM TESTING
Check PCV hose, grommet, breather hoses, and connections for cracks, damage, deterioration, and obstructions. Ensure that all connections are tight.
With engine idling, remove PCV valve from breather chamber (from valve cover on Accord). Listen for clicking noise while blocking and unblocking end of PCV valve with finger. If no clicking noise is heard, replace PCV valve and retest.
Inspect blow-by filter and replace if it is clogged with dirt and dust, or if it is stuck and dripping oil.