If troubleshooting high crankcase pressure, the following items can cause the closed crankcase ventilation valve to
close during engine operation:
โข High air intake restriction. Refer to Procedure 010-031 in Section 10.
โข A restricted crankcase ventilation filter. Refer to Procedure 003-021 in Section 21 ..
โข A malfunctioning or misassembled closed crankcase ventilation valve.
The closed crankcase ventilation valve should allow crankcases gases to flow when the engine is not running
and/or removed from the engine.
NOTE: Application of air can be applied either to the inlet or outlet of the closed crankcase ventilation valve.
A small amount of air can be blown through the closed crankcase ventilation valve (less than 34 kPa [5 psi]) to
check the closed crankcase ventilation valve.
If air does not go through the closed crankcase ventilation valve, verify that the closed crankcase ventilation valve is:
โข Assembled correctly.
โข Not plugged or damaged internally.
Correct or replace any malfunctioning or damaged parts.
