See Figure 1
The PCV valve is an emission control device operated by intake manifold vacuum to prevent crankcase blow-by gases from escaping into the atmosphere. When the engine is running at idle, the valve opens slightly to allow a small amount of blow-by gas to be drawn into the intake manifold/dynamic chamber where it mixes with intake air for combustion in the cylinders. As engine speed increases, the valve opens to allow more of the blow-by gases into the chamber.
1978-82 GLC and 1979-82 626
- With the engine idling and fully warmed up, unclamp and remove the hose leading to the PCV valve at the valve.
- Place your finger over the open end of the hose to stop airflow. If the idle speed drops, the valve is working properly and should be reinstalled. If the idle speed does not change, replace the valve.
See Figure 2
- Warm up the engine and allow it to run at idle speed.
- Disconnect the PCV valve with the ventilator hose from the valve cover.
- Cover the valve opening with your finger and listen for a change in the idle speed.
- If the idle speed drops, the valve is working properly and should be reinstalled. If the idle speed does not change, replace the valve.
See Figure 3
Since rotary engines are not equipped with a PCV system, there is no inspection or replacement procedure for a PCV valve. Instead, blow-by gases in the crankcase are kept from being released into the atmosphere by a ventilation and check valve on 1979-80 models, or