Indications:

• Gradual increase in exhaust temperature.
• Hissing noise from the air intake valve.
• Black smoke from the funnel.

Effects:

• Drop in compression and peak pressure.
• Carbon deposition in intake passages and manifolds.
• Turbocharger surging.
• Scavenge failure.

Corrective Action:

• Lap the valve and seat to restore the seal.
• Replace the valve if necessary.

Leaking exhaust valve:

Indications:

• Gradual increase in exhaust temperature.
• Black smoke and sparks from the funnel.

Effects:

• Reduction in compression and peak pressure.
• Fouling and surging of the turbocharger.

Corrective Action:

• Clean and lap the valve to restore its sealing capability.
• Replace the valve if required.
• Maintain fuel equipment to ensure proper combustion.

Indications:

• Heating of the air line; thermal strip changes color.
• Peeling of paint on the air manifold.
• Smoke from the starting air line drain.
• Manifold feels hot when touched.

Effects:

• Risk of starting air line explosion.
• Bursting of the safety disc.
• Relief valve activation.

Corrective Action:

• Shut off the affected unit by cutting off the fuel supply.
• If possible, replace the faulty air start valve with a spare, overhauled one.

Indications:

• Increase in jacket cooling water (JCW) temperature for the affected unit.
• Fluctuations in JCW pressure.
• White smoke from the funnel.
• Decrease in exhaust gas temperature.
• Increase in expansion tank water level.
• Water discharge from scavenge drains.

Effects:

• Contamination of lube oil with water.
• Mixing of exhaust carbon with JCW.
• Knocking of the affected unit.

Corrective Action:

• Shut off the JCW inlet and outlet to the affected unit.
• Cut off fuel supply to the unit.
• Replace the liner if possible.

Indications:

• Blow-by gases in the crankcase.
• Black smoke from the funnel.
• High exhaust temperature.
• Lube oil contamination.
• Increased scavenge air temperature.

Effects:

• Risk of scavenge fire.
• Reduced compression and peak pressure.
• Decreased power output.
• Accelerated liner wear.
• Increased fuel oil consumption.

Corrective Action:

• If immediate replacement is not possible, isolate the affected unit.
• Replace the broken piston rings with new ones.