I'm reluctant to use these products. I had a bad experience in the ancient past where it cleaned too well and the head gasket soon failed. This was on another make and model. You could remove the radiator and soak it separately using a warmed up diluted version of what you're showing. With the engine cold, take the radiator cap off and look inside to see if it needs flushing. When I have my radiator off, I usually back flush it with a garden hose hose and then final rinse it with distilled water. Walmart has the best price on distilled water, usually.