STP Engine Flush for Petrol and Diesel Engines. Adding STP Engine Flush directly to the used motor oil prior to draining helps neutralise engine acids while it works to loosen and remove sludge, varnish and gum deposits that ordinary draining leaves behind.
Free sticking internal engine components
Improve lubrication life and protection of the new oil
Prevent contamination of new oil by removing contaminants left behind by ordinary draining