Give your 2004.5-2005 Chevy/GMC 6.6L LLY Duramax the Coolant & Additives it needs to stay on the road. In addition to reducing surface tension for more effective cooling, these additives also offer faster warm-up times, corrosion prevention, and lower engine temperatures. In addition to full synthetic antifreezes, you can also get additional additives that provide you with a coolant service life of 150,000 to 750,000 miles. XDP carries Mishimoto, Evans, Hot Shot's Secret, XDP, Lucas Oil, DEI, Royal Purple and more.