Crankcase Pressure Check
1. Bring the engine to operating temperature with the air filter installed.
2. Obtain a water manometer (special tool J 23951).
3. Remove the engine oil dipstick and attach the hose of the water manometer to the oil disptick tube.
4. Start and run the engine at idle speed, observing the water manometer reading (see Figure 6-22):
• If the reading indicates that crankcase pressure is approximately 1 inch of pressure or less, go to step 5
• If the reading indicates that crankcase pressure is higher than 1 inch of pressure, inspect the Crankcase
Depression Regulator Valve (CDRV) and re-check crankcase pressure (if the CDRV checks good, perform a compression test).
Example: 4 inches of pressure is higher than 1 inch of pressure.
5. Run the engine at 2,000 rpm, observing the water manometer reading (see Figure 6-23):
• If the reading indicates that crankcase pressure is approximately 2 to 5 inches of vacuum, go to step 6.
• If the reading indicates that crankcase pressure is lower than 2 inches of vacuum, inspect the CDRV and re check crankcase pressure (if the CDRV checks good, check the air intake/exhaust systems).
Example: 8 inches of vacuum is lower than 2 inches of vacuum.
• If the reading indicates that crankcase pressure is higher than 5 inches of vacuum, inspect the CDRV and re check crankcase pressure.
Example: 1 inch of pressure is higher than 5 inches of vacuum.
6. Separate the hose of the water manometer from the oil dipstick tube and install the engine oil dipstick.
7. Stop the engine.
