First of all, it’s important to specify the right oil weight for your machine in order to save you time and money. The first type is 10W-30 synthetic oil that works well in temperatures below 40F. This oil will provide protection from wear under these conditions and prevent water or water and rust from entering the engine through the crankcase ventilation system. It is suitable to be mixed with detergent, which increases its effectiveness even more. When you own a gas-powered pressure washer, then you might think applying the 30W non-detergent oil will not make much of a difference. After all, it is only needed in gears and bearings.