Diesel
engines operate at twice the compression ratio of gasoline engines; create
greater internal pressures and heat. Components are made to closer
tolerances, therefore are more easily damaged by dirt, corrosion improper
fuel and lubricants.
Diesel injectors are expensive precision parts that handle fuel pressures as high as 137,900 kPa. Using correct diesel fuel is essential because it not only runs the engine, but also lubricates and cools the fuel pump, injectors and spray tip.
Dripping or leaking injectors can cause rough engine operation, destructive unbalanced cylinder temperatures, crankcase oil dilution and incomplete combustion. Because of diesel fuel’s acid content, combustion by-products are more corrosive. Greater diesel heat also converts combustion by-products to varnish inside the engine more rapidly.
Dirt and water by passing fuel filters can badly score fuel pump and injectors, requiring replacement. Rust can cause sticking in pump pressure regulator valves. Water in fuel can also cause hard starting, uneven running and frequent stalling.
Because diesel engines breathe more air per hour than gasoline engines, air leaks through cracks, loose connections or holes in flexible hoses can cause serious and expensive engine damage. Clogged air filters reduce power.
Diesel engines make more use of oil as coolant because of greater heat and pressure. For example, the oil cools piston undersides. Improperly or inadequately filtered oil can cause scoring and damaging of engine parts. Inadequate circulation of oil and coolant can cause engine overheating and thermal distortion.
Poor quality fuel can cause hard starting, incomplete combustion with varnish build-up, smoky exhaust, and plugged fuel filters in cold weather.