Oil is a basic component of all gas-powered pressure washers and is used to lubricate the water pump as well as the engine. The type of oil is also important to keep these two moving parts in prime working condition.
Gas-powered pressure washers use two distinct types of oil. One is the four-stroke engine oil for the gas engine, the same as in your lawnmower, while the other is a non-detergent, non-foaming oil with rust inhibitors for the pressure washer's water pump.
The oil in the pump lubricates the pump plungers and connecting rods, keeping the pump working smoothly at high pressure loads. The oil in the engine lubricates the pistons and rods and protects the engine from heat build-up.
The recommended oil for pressure washer pumps is DP70 pump oil, a non-detergent blend with rust inhibitors.
The gas engine on your pressure washer uses 30W four-stroke motor oil. For areas with a wide range of temperatures, 10W-30 oil is recommended.
Change the oil in your water pump after the first 10 hours of operation, and every three months or 250 work hours thereafter. The engine oil should be changed after the first 20 hours of use, and every six months or 100 hours after that.