Diesel mechanics diagnose engine trouble, dismantle the engine when necessary, and replace or repair defective parts.

They reassemble the engine and repair mechanical and electrical faults in construction machinery. In most cases electrical diagnostic equipment is used to locate problems – experienced diesel mechanics are able to locate a problem by listening to the noise in the engine. Mechanical parts are replaced or minor adjustments made.

Diesel mechanics also complete job cards, furnish information on the parts that should be ordered and assist in training learners. They often perform administrative and managerial tasks. Working conditions of the diesel mechanic vary according to the place of employment – for instance, a well-equipped workshop or farm, ship or construction site.