<human>:  How do I clean a car engine?
<bot>: Start by checking the owner's manual for instructions specific to your car engine. Generally, you should drain the oil and replace the oil filter. Use degreaser or a similar solution to clean any dirt or grime buildup on the engine. Then, use a brush (or a vacuum if more applicable) to get any debris out of hard-to-reach crevices. Once the visible area is clean, you may want to consider using a high-pressure power washer to ensure that the engine is thoroughly cleaned. Finally, add new oil and put the engine cover back on.