Compression Test

WARNING: This page is about a different variant/trim than selected.

1.

Make sure the oil in the crankcase is of the correct viscosity and at the correct level.

2.

NOTE: Failure to remove all glow plugs may result in inconsistent test results.

Remove the glow plugs. Refer to: Glow Plugs .

NOTE: The battery charger must be left connected during the compression test and disconnected when the test is complete.

3.

Connect a battery charger to the battery.

GFD144213

Courtesy of FORD MOTOR COMPANY

4.

Install the Compression Test Adapter (303-1305) and a commercially available diesel compression tester.

NOTE: Note the approximate number of compression strokes necessary to obtain the highest reading.

5.

Install an auxiliary starter switch in the starting circuit. With the ignition switch in the OFF position, and using the auxiliary starter switch, crank the engine a minimum of 5 compression strokes and record the highest reading.

6.

Repeat the test on each cylinder, cranking the engine approximately the same number of compression strokes.
- There must not have no more than a 20% difference from the average on any given cylinder.

7.

Investigate and repair any cylinder(s) that are outside the 20% range.

GFD144213

Courtesy of FORD MOTOR COMPANY

8.

Remove the Compression Test Adapter (303-1305) and the commercially available diesel compression tester.

9.

Disconnect the battery charger from the battery.

10.

Install the glow plugs. Refer to: Glow Plugs .