Diesel Power Washers

Diesel makes sense when you need consistent output away from a socket. The engine runs at fixed RPM under load, so pump pressure stays steady—useful for stripping yard equipment, washing plant, blasting oil or mud off chassis. Runtime depends on tank size and throttle setting; most units here run several hours between refills. Fuel cost per hour is higher than electric, but you're not hunting for a generator or dragging extension cable.

Check the pump spec first: pressure in bar or PSI, flow in litres per minute. Higher pressure cuts faster through baked-on grime; higher flow clears loose dirt and rinses quicker. Match both to the work—3000 PSI at 15 L/min handles most site cleaning, but if you're mostly rinsing aggregate or washing down lorries, flow matters more than peak pressure. Pumps are usually triplex plunger, brass or stainless head. Ceramic plungers last longer under abrasive use.

Engine choice affects service intervals and parts supply. Yanmar and Loncin are common in this category—parts are stocked locally, manuals are straightforward. Diesel fuel needs to stay clean; fit an inline filter if the onboard one is coarse, and drain the separator regularly. Cold starts improve with a block heater or fresh fuel in winter. If the machine sits unused for weeks, run it dry or dose the tank with stabiliser.

Frame and wheel size matter if you move the washer often. Pneumatic tyres handle rough ground better than solid castors. Hose reel, gun holster, and detergent tank are useful but not standard—check what's included. Most units ship with a trigger gun, lance, and a set of nozzles (0°, 15°, 25°, 40°, soap). Replace nozzles when the orifice wears oval; pressure drops and the fan pattern goes ragged.