DescriptionStar cool is the best choice for all high-performance engines. With a service life of up to 2+ years, 250,000 miles or 4,000 hours in gasoline engines (750,000 miles, 7+ years or 12,500 hours in diesel engines) it goes significantly beyond all OEM specifications. Star cool passivates metal surfaces to create a barrier to corrosion and will seal pinhole leaks or small cracks. Pre-mixed with de-ionized water, it is ready to use and safe for all water-cooled gas or diesel-powered engines. Star cool is ideal for year-round use; protecting against boilover to 265 DegreeF and freezing to -26 DegreeF (with 15 psi cap).