We want to tell you that your radiator additive has kept our engine cleaner than ever. Our Corvette competes in SCA racing and every winter we tear it down and refresh the engine and some other components. From years past, we got used to seeing a brown residue inside the heads, manifold and areas where the coolant passes through. And we also would always see brownish orangish gunk inside the radiator cap. But this year it was spotless! We feel it is because last year was the first full year we ran your supercoolant in our radiator. Now we're telling everyone we can. If you want to keep it clean, pour in a bottle of the Lucas radiator additive. It DOES work. Very happy with your product. Thank you Lucas. -Bill Thomas