A loss of cylinder pressure can cause increased oil consumption. The detection and elimination of cylinder pressure losses is vital to engine life and efficient operation. To assist the mechanic in effectively measuring the loss of cylinder pressure, and locating the source of abnormal leaks in individual cylinders, the following test procedure has been developed.
1. Move the vehicle requiring test to the chassis dynamometer; refer to OEM guidelines.
2. Disconnect air compressor.
3. Start the engine.
4. Run the engine and bring the engine coolant temperature to normal operating range.
5. Run vehicle to full load and rated speed.
6. Attach a manometer calibrated to read in inches of water, to the oil dipstick opening. Measure and record the crankcase pressure.
7. Shut down engine.
8. Remove the vehicle from the chassis dynamometer.
9. Review the crankcase pressure test results.
If the crankcase pressure exceeds 0.75 kPa (3 in. H 2 O), repair worn or damaged valve(s) or cylinder kit; r
If the crankcase pressure was less than or equal to 0.75 kPa (3 in. H 2 O), perform cylinder compression test.
10. Compare the cylinder compression test results to specifications.
If the cylinder compression is below specifications, repair worn or damaged valve(s) or cylinder kit;
If the cylinder compression is within specification, call Detroit Diesel Technical Service Group
