DESCRIPTION & OPERATION
Vehicles use a closed dual return type crankcase ventilation system. This consists of a PCV valve, a hose connecting the valve cover with the PCV valve, and a breather hose connecting the air cleaner with the valve cover.
When intake manifold vacuum is high, the PCV valve draws blow-by gases from the valve cover into the intake manifold for burning. When intake manifold vacuum is low (during wide open throttle), blow-by gases flow from the valve cover into the air cleaner where they mix with intake air.
Crankcase Ventilation System. Scheme 12
MAINTENANCE
Every 30,000 miles or every 2 years, test PCV valve operation. Inspect hoses for damage, deterioration, and obstructions.
PCV VALVE
| CAUTION | Do not suck air through the PCV valve. The fuel vapor and petroleum substances inside the PCV valve are harmful. |
- Disconnect PCV hose at breather hose and run engine at idle. Place finger over end of PCV hose and check that there is vacuum. If not, check hose and PCV valve for clogging. Replace PCV valve and/or hose if clogged and retest.
- With engine off, remove hose from PCV valve and install a new hose on PCV valve. Blow air into hose and check that air flows with difficulty through PCV valve into intake manifold. If air flows easily through PCV valve, replace PCV valve. Use sealing tape on threads when installing PCV valve in intake manifold.