Crankcase ventilation system Inspection/Diagnosis
Results of incorrect operation
- Clogged holes or hose of the positive crankcase ventilation system (PVC) may lead to the following:
- Rough idle
- Engine stall or low idle
- Oil leaks
- Oil in the air filter
- Sludge in the engine
- A leaky orifice or PVC system hose can cause the following conditions:
- Rough idle
- Engine stop
- High idle speed
Function test
In these systems, there may appear: excess gas flow compared to the throughput of the system due to significant engine wear, as well as prolonged heavy load, etc. In this case, the gases are ejected into the air filter, and then sucked into the engine.
Proper operation of the crankcase ventilation system depends on the quality of the engine seal. If deterioration in oil flow conditions or oil thinning is noted, but the crankcase ventilation system is operating normally, check the engine for a possible cause. Fix all problems.
If the engine idles erratically, it is necessary to check whether the opening of the PVC system is clogged, whether the ventilation filter, air filter and hose are clogged. Replace if necessary. Perform the following procedures:
- Disconnect the positive crankcase breather hose from the cylinder head cover.
- Let the engine run at idle.
- Place your thumb over the end of the vent hose to check for vacuum. If there is no vacuum in the ventilation hose, check according to the following points:
- Clogged hoses
- manifold hole
- Turn off the engine.
- Carefully inspect the PVC hole in the cylinder head cover for metal chips or blockage.