Prior to troubleshooting a high crankcase pressure, perform the following procedure:
- High crankcase pressure can occur if there are obstructions in the crankcase ventilation system. The maintenance section of the Operation and Maintenance Manual contains procedures for cleaning the components of crankcase ventilation system. Refer to Operation and Maintenance Manual, "Engine Crankcase Breather - Clean" and refer to Operation and Maintenance Manual, "Crankcase Fumes Fitting - Inspect/Clean".
- Clear the diagnostic code.
Use this procedure in order to troubleshoot a high crankcase pressure or use this procedure if one of the following diagnostic codes is active. Access the engine monitoring system on Caterpillar Electronic Technician (ET) in order to view the current trip points for these codes. Refer to Troubleshooting, "Engine Monitoring Parameters" for information about engine events.
| Engine Event | ||
|---|---|---|
| J1939 Code and Description | Conditions that Generate the Code | System Response |
| 101-15 Engine Crankcase Pressure : High - least severe (1) | The Engine Control Module (ECM) activates this code when the crankcase pressure has exceeded the limit for a programmed period. The amber warning lamp is illuminated. | The code is logged.
This code can be caused by an obstructed tube, an obstructed filter, or an obstructed hose. |
| 101-16 Engine Crankcase Pressure : High - moderate severity (2) | ||
| |
| Illustration 1 | g02054714 |
|
Left side engine view (1) Crankcase pressure sensor | |
| |
| Illustration 2 | g02213453 |
|
Components for the crankcase ventilation system (2) Filter housings (3) Fumes disposal tube (4) Breathers (5) Oil drain tube (6) Check valve | |
- Plugged crankcase breather
- Faulty check valve
- Faulty sensor
- Worn engine components
A plugged crankcase breather will cause excessive crankcase pressure. Leakage of the crankshaft seal can occur. Sealing of the piston rings can be lost. An increased crankcase pressure will typically lead to an increase in the crankcase blowby. Clean the crankcase breather according to the Operation and Maintenance Manual, "Engine Crankcase Breather - Clean".
The 8T-2700 Blowby/Air Flow Indicator is used to check the amount of blowby. Refer to Special Instruction, SEHS8712, "Using the 8T-2700 Blowby/Air Flow Indicator" for the test procedure for checking the blowby.
A faulty check valve can cause excessive crankcase pressure. A faulty check valve will not allow the crankcase to vent properly. Clean the check valve or replace the check valve.
If you suspect that the crankcase pressure sensor is faulty, replace the sensor with a sensor that is known to be good.
Damaged pistons, rings, or cylinder liner can cause too much pressure in the crankcase. This condition will cause the engine to run rough. A greater amount of blowby will be exiting the crankcase breather. The breather will become restricted in a short time, causing oil leakage at gaskets and seals that would not normally have leakage. Blowby can also be caused by worn valve guides or by a failed turbocharger seal.