Does it hurt to change viscosity oil in a engine?

Changing the viscosity of oil in an engine can potentially cause issues if the new oil is not suitable for the engine's design or operating conditions. Using oil with a significantly different viscosity than recommended can lead to inadequate lubrication, increased wear, or reduced performance. However, if the new oil viscosity is within the manufacturer's specifications, it should not hurt the engine. Always consult the owner's manual for the appropriate oil viscosity.