1. Excessive bore wear - the liner bore worn beyond the maker's/Class maximum wear limit, causing loss of compression, high blow-by and oil consumption.
2. Cracking of the liner - cracks in the bore, at the ports, at the top flange or in the water space.
3. Scuffing/ scoring - deep scoring or scuffing of the bore surface that cannot be honed out within limits.
4. Corrosion/ pitting - severe pitting or corrosion of the bore or water side.
5. Distortion/ ovality - the liner out-of-round or tapered beyond limits.
6. Damage to the port area/ lands - broken or cracked port lands.
7. Repeated ring/ piston failures attributable to the liner condition.

1. Stop the engine, secure the turning gear, drain the jacket cooling water and isolate the water/oil connections to the unit.
2. Remove the cylinder head (cover) complete with its valves/injectors, and land it clear.
3. Remove the piston: disconnect the connecting rod from the crankshaft (remove the big-end), lift the piston (with rod) out of the liner, and land it on blocks.
4. Remove the stuffing box/ liner bottom parts as required.
5. Mark the liner and the jacket for correct orientation/ port alignment.
6. Disconnect the liner cooling water connections and any liner lifting gear.
7. Break the liner from its seating using the lightweight jacking screws/ liner lifting arrangement, then lift the liner out of the jacket with a suitable sling.
8. Clean and inspect the jacket bore and the liner seating.

1. Clean the jacket bore and the liner seating thoroughly; inspect for cracks and verify the water spaces are clear.
2. Fit new O-ring/ soft packing seals in the liner grooves, greased.
3. Lower the new liner into the jacket using a sling, aligning the port marks so the ports line up with the jacket ports.
4. Seat the liner fully on its seating; check it is not rocking and that the lands align.
5. Refit the stuffing box, reconnect the connecting rod/ piston, refit the piston (with new rings checked) and the cylinder head, torquing the studs in sequence.
6. Reconnect the water/oil connections.

Before fitting:

• Liner bore size/ identification and surface finish; correct oversize/ standard.
• Ring/groove dimensions and ring gaps; piston/liner clearance.
• Port alignment marks and the condition of the new sealing rings.
• Cleanliness of the jacket and the liner seating; correct fit-up dimensions.

After fitting:

• Piston/liner clearance and ring end gaps; ring free movement.
• Port alignment and the liner lands.
• Pressure test the cooling water side (jacket) for leaks.
• Bar the engine over to confirm free rotation and no tight points.
• Run the unit and check compression, exhaust temperature and cooling water temperature.