How do you change the oil pump for 3100?

To change the oil pump on a 3100 engine, first ensure the vehicle is on a level surface and the engine is cool. Drain the engine oil and remove the oil pan to access the oil pump. Disconnect the pump from the engine block, replace it with a new pump, and reassemble everything, ensuring all gaskets are properly sealed. Finally, refill the engine with oil and check for leaks.