The short answer is yes, you can use a 20w40 oil in place of a 15W40 oil. However, there are a few things to keep in mind when making this switch. First, the viscosity of the oils will be different. A 20w40 oil will be thicker than a 15W40 oil, which means it will take longer for the engine to start and idle. Second, the 20w40 oil may also cause more wear and tear on the engine because it has a higher viscosity. ..
