I achieved about a 5 degree improvement (operating temperature before coolant - 210, after Purple Ice - ~205). The spec sheet indicates a 6 degree improvement on their tests with the engine specified, so I'm pretty happy with my results. I used in a 2005 Escalade V8 6.0.I've had good success with other Royal Purple products and am counting on this product to perform as described in terms of reducing hot spots, keeping the system clean and extending water pump life, as my Escalade enters it's "golden years".