Generally chemical cleaning is done by engine manufacturers during the various process of manufacturing of the engine/engine block and its components; after casting, boring, drilling, reaming, honing, etc. In many cases the engine block is placed in a “washing machine” and cleaners are pumped under pressure or at elevated temperatures so that grime/dirt/sward and other contaminants are flushed out from the various lines, holes and crevices of an engine block. Most of the Alkali based chemicals are powders by nature and water is added to form a solution and temperature may be elevated to aid cleaning. For extremely grimly, oily surfaces standard solvents may also be added for good results. After this the engines are dried and hot air is used to flush out remains of the cleaning solutions.
A lubricant specialist, I am allergic to introducing “chemicals/foreign material” into
Engines. Having worked with Castrol in India for over 17 years have sold a number of lubricants, specialities and cleaners. I am surprised at the “quick change and flushing indicated by you. The cleaners I know are broadly classified as Alkali Cleaners and Solvents. In both case the science behind the cleaners is “to reduce the surface tension” to loosen the dirt particles and allow the flushing of the dirt particles.
I would like to know of one good reason why we should adopt the manufacturing industry practice for cleaning in an oil change. It may be noted that during major overhauls (and when engine is stripped open) some "solvent" cleaning is done in some form or another.
During lube oil change the practice is to do flushing. Old oil is drained out and filled with flushing oil. This is circulated through the system by running the engine for a few minutes and then drained off. For dirty systems this may be done more than once. Finally the engine is filled with fresh engine oil.
M Hussam Adeni