Always follow the manufacturer's specified oil change interval - typically expressed in hours (for agricultural engines) or kilometres (for road vehicles). Modern diesel engines often specify extended drain intervals of 500+ hours or 20,000–30,000km for road vehicles using the correct longlife oil, but these intervals assume the correct oil grade is used from new. For older engines, or engines operating in dusty or cold conditions, shorter intervals are advisable. When in doubt, err on the side of more frequent changes - oil is cheap compared to the cost of engine damage from degraded lubrication.

Diesel bug is a collective term for microbial contamination in stored diesel or kerosene - bacteria, yeast and fungi that colonise the fuel-water interface at the bottom of storage tanks. They produce a dark, sludgy biomass and generate corrosive acids that attack metal tanks, rubber seals and injection equipment. Signs include dark staining or slime on tank gauge glasses, blocked fuel filters, and a sulphurous smell. Treatment involves adding a biocide product to kill the contamination, followed by filtering or draining the sludge from the bottom of the tank. Prevention is much easier than cure - use a biocide additive regularly, particularly if fuel is stored for more than a few weeks.

AdBlue consumption on modern agricultural tractors is typically 3–5% of diesel consumption, though this varies with load, engine speed and the specific SCR calibration. A tractor consuming 20 litres of diesel per hour might therefore use 0.6–1 litre of AdBlue per hour. At peak workload, a 200hp+ tractor in a harvest scenario could deplete its AdBlue tank in 20–40 hours of work. Checking and replenishing AdBlue at fuel fills is a simple habit that prevents the inconvenience of an SCR derate lockout at a critical moment.

No - this is a common and potentially damaging mistake. Car engine oils are not suitable for use in agricultural diesel engines, which have fundamentally different requirements including higher levels of alkaline reserve (Total Base Number) to neutralise acids from higher sulphur fuel combustion, different additive packages to handle agricultural diesel fuel contamination, and compatibility with wet clutch and brake systems if the engine oil also lubricates those components. Always use an oil specified by your tractor's manufacturer for the engine type and application.