- how to clean car engine? For areas with tough grime or oil stains, use a soft-bristled brush to scrub the surfaces gently. Focus on parts like the valve cover, intake manifold, and other visible engine components. Avoid using abrasive brushes that could scratch or damage sensitive parts, especially plastic or rubber elements. Visit - https://tagoreautomotive.com/is-cleaning-inside-of-car-engine-necessary/