The PCV valve on the toyota 4A-FE petrol engine is located on the centre of the rocker cover connected directly by a rubber hose to the intake manifold. When we clamped this hose, the idle speed dropped slightly. This is because the crankcase gases are not venting back into the intake manifold. When we pulled the PCV valve out of the rocker cover, and put my thumb over the end, the PCV clicked shut due to the vacuum inside the manifold. This click means it is working properly. There is also a 'fresh air hose' that goes from the throttle body to the rocker cover. If the PCV valve gets blocked up, oil and gasses get into throttle body and air cleaner through this air hose.
Sunday, July 31, 2011
PCV valve
The PCV valve on the toyota 4A-FE petrol engine is located on the centre of the rocker cover connected directly by a rubber hose to the intake manifold. When we clamped this hose, the idle speed dropped slightly. This is because the crankcase gases are not venting back into the intake manifold. When we pulled the PCV valve out of the rocker cover, and put my thumb over the end, the PCV clicked shut due to the vacuum inside the manifold. This click means it is working properly. There is also a 'fresh air hose' that goes from the throttle body to the rocker cover. If the PCV valve gets blocked up, oil and gasses get into throttle body and air cleaner through this air hose.
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