| • | Improper oil viscosity. Install recommended oil viscosity for expected temperatures. | 
| • | Excessive piston to bore clearance. | 
| • | Excessive piston pin to piston clearance. | 
| • | Excessive crankshaft end clearance. | 
| • | Excessive crankshaft bearing clearance. | 
Some engine noise may be normal for 1-3 seconds at start-up. Be sure that any noise that is identified is really coming from the engine. (i.e. ABS initialization noise)