Valve Noise

• Inadequate valve clearance

Adjust the valve clearance.

• Abrasion of the valve stem or guide

Replace the valve stem or the guide.

• Weak valve spring

Replace the spring.

Piston, Ring, Cylinder Noise

• Abrasion of the piston, the ring, or the cylinder

Bore the cylinder or replace the piston, the ring, or the cylinder.

Connection Rod Noise

• Abrasion of the connection rod bearing

Replace the bearing.

• Loosened the connecting rod nut

Tighten to the specified torque.

Crankshaft Noise

• Abrasion of the crankshaft bearing

Replace the bearing.

• Abrasion of the crankshaft journal

Grind or replace the crankshaft journal.

• Loosened bearing cap bolt

Tighten to the specified torque.

• Excessive clearance of the crankshaft thrust bearing

Adjust or replace.

• Low oil pressure

Refer to High or Low Oil Pressure .