(a) Particles of metal have been found in the oil filter of a diesel engine crankcase. Describe how the nature and source of these particles may be determined. (5)

(b) (i) State the possible reasons for crankcase lubricating oil filters becoming choked over periods with the necessity for frequent cleaning (3)

(ii) Describe how this problem may be reduced (3)

(c) State the effect that restricted oil flow can have on different parts of an engine. (5)