Which of the following properties are essential requirements for heavy-duty tractor engine crankcase lubricating oils?
Options:
(A) High Viscosity Index (VI) to minimize viscosity change across wide operating temperatures
(B) Adequate Total Base Number (TBN) to neutralize acidic combustion by-products from fuel sulfur
(C) Low pour point to ensure oil flow and pumpability during cold morning starts
(D) High flash point to prevent oil vaporization and crankcase fire hazards
Answer Key:
A, B, C, D
Step-by-Step Solution & Explanation
All four properties are crucial for tractor crankcase lubricants:
• High VI maintains hydrodynamic lubrication film across temperature swings.
• TBN counteracts sulfuric acid corrosion from diesel combustion.
• Low pour point prevents oil gelling in cold weather.
• High flash point ensures thermal stability and safety against ignition.