PRODUCT INFORMATION
INDEX
DATE
Dep. 2
IO-C-M-25-011e
May 2006
MAINTENANCE OF THE CRANKCASE GAS
RECIRCULATION SYSTEM
3/3
2. TROUBLESHOOTING
At times, the filter clogging indicator will rise when starting the engine after a certain period shut down. This
occurs because the cooling of oil in the outside of the filter leads to an increase in head losses. Once warm, oil
drips and the system operates correctly again.
To check that the filter works alright, remove the cap from the indicator and push the indicator downwards with
your finger, when the engine has warmed up. If the indicator does not rise again, the filter is in good condition. If
after pushing the indicator down, it rises again, change the filtering cartridge even if the specified hours of
operation for maintenance have not been reached.
When the engine is fitted with a crankcase gas recirculation system, it is advisable to measure the crankcase
pressure periodically (every 200 hours). This pressure, being indicative of the balance between the amount of
engine-generated blow-by gas and the exhausted quantity, may denote the occurrence of a failure.
The following table shows the relation between the crankcase pressure and the engine components, suggesting
corrective actions.
Crankcase pressure CAUSE
ACTIONS
from –4 to +3 mbar
System ok. Pressure varies from -4 to +3 mbar
in time
None
Greater than +3 mbar
Filter clogged.
Possible high blow-by (rings and liners)
Check clogging indicator. Change filtering
cartridge. Check to see if the valve has been
closed by mistake.
Inspect the pipeline of the system to detect any
plug or undesired throttling of the gas flow.
Measure the crankcase pressure level, after
disconnecting the recirculation system, i.e. at
atmospheric pressure (by opening the oil filling
plug). See IT-C-A-25-016.
Less than –4 mbar
Pressure control valve wide open.
High exhaust of blow-by gases.
Check the valve condition.
Check the air filters for good condition.
Many fluctuations
Condensate build-up in the system.
Make sure the entire run of pipes of the system is
free from spots where condensates could gather.
Verify if the hoses of the system are subject to
excessive ventilation, leading to large amounts of
condensate developing in the hoses. If yes, lag
the cold spots.
5.2.15
O&M_2.002211.810_A_10_2016
