- With reference to the engine log books, explain the reasons for recording EACH of the following, and the effect on the engine should the temperatures be outside the normal parameters:
(a) exhaust temperatures;(3)
(b) cooling water inlet/outlet temperature;(3)
(c) lubricating oil temperature.(4)
Engine Log Books – Temperature Entries
(a) Exhaust temperatures (3 marks)
- Reason for recording: To monitor combustion efficiency and cylinder performance; assists in detecting faults such as injector malfunctions, scavenge fires, or poor compression.
- Effect if outside parameters:
- High: May cause thermal overload, burning of exhaust valves, piston crown damage.
- Low: May indicate poor combustion or scavenge air problems, leading to fouling and incomplete burning.
(b) Cooling water inlet/outlet temperature (3 marks)
- Reason for recording: To ensure efficient heat transfer and prevent thermal stresses in engine components.
- Effect if outside parameters:
- High: May cause overheating, thermal expansion, liner seizure, and breakdown of lubricating oil film.
- Low: Causes inefficient fuel combustion, increased thermal shock, and risk of liner cold corrosion due to sulphuric acid condensation.
(c) Lubricating oil temperature (4 marks)
- Reason for recording: To confirm the oil is maintained at the correct viscosity for effective lubrication, cooling, and cleaning of engine parts.
- Effect if outside parameters:
- High: Oil film breakdown, loss of viscosity, bearing failure, scuffing and seizure of moving parts.
- Low: Oil too viscous, poor circulation, inadequate lubrication, and sludge formation.