Another interesting question would be:
How would the engine cleaning compare given a choice of:
3 engine flushes with a solvent like straight hydrotreated cycloalkanes (STP Super Concentrated High Mileage Engine Flush)
versus
3 separate oil change intervals of 4k with a new 1 quart HPL EC 30 added with each oil change.
Cleaning criteria might be: Sludge, Varnish, and Piston ring cleaning.
How would the engine cleaning compare given a choice of:
3 engine flushes with a solvent like straight hydrotreated cycloalkanes (STP Super Concentrated High Mileage Engine Flush)
versus
3 separate oil change intervals of 4k with a new 1 quart HPL EC 30 added with each oil change.
Cleaning criteria might be: Sludge, Varnish, and Piston ring cleaning.