Compression Test
WARNING: This page is about a different variant/trim than selected.
Special Tools
| Illustration | Tool Name | Tool Number |
|---|---|---|
| Adapter, Crankcase Pressure Test | 303-757 |
- Make sure the oil in the crankcase is the correct viscosity and at the correct level.
- Operate the engine until it is at normal operating temperature. Turn the ignition switch to the OFF position.
- Remove the glow plugs. For additional information, refer to appropriate GLOW PLUG SYSTEM service information.
- Connect a battery charger to the battery.
- Install the Crankcase Pressure Test Adapter and a commercially available diesel engine compression gauge.
- Install an auxiliary starter switch to the starting circuit. With the ignition switch in the OFF position, crank the engine a consistent number of strokes (minimum of 2 compression strokes to 12 compression strokes). Record the readings.
- Repeat the test on each cylinder, cranking the engine the same number of compression strokes, record the readings. Compare the readings of the 8 cylinders.
- There must be no more than a 10% difference between the readings.
- Investigate and repair any cylinder(s) that are outside of the 10% range.
- Install the glow plugs. For additional information, refer to appropriate GLOW PLUG SYSTEM service information.
NOTE:
Failure to remove all the glow plugs may result in inconsistent test results.
NOTE:
The battery charger must be left connected during the compression test and disconnected when the test is complete.
NOTE:
It may be necessary to install a commercially available adapter fitting to connect the Crankcase Pressure Test Adapter to the commercially available diesel compression gauge.