I tested the product in a pot of water when it started to boil. It opened at 180 degrees, but if you have a mostly stock 5.3 Silverado, don't waste your money. My truck is still running at 210 degrees. I haven't seen a lower operating temperature yet. Maybe the truck will run colder when I hit the track or when winter sets in, but I haven't noticed a difference yet. Even if you buy this product because you need a stage 2 jet engine, don't waste your money. I recommend using level 2 or 1. Soft…