I did this therapy to a renault grand scenic 1.9dci.the product is fantastic it removes alot of carbon and does not hydrolock the engine.fantastic bravo i recommend very fast shipme t only 7 days it came to house.i will order again.i dont know if it unstsuck my piston rings but a few morw times and it will.alot of carbon gets out of combustion chamber.👍👍👍👍