Just some friendly advice, if you decide to run any sort of engine flush in your engine, I HIGHLY suggest that you drop your oil pan afterwards and clean out the pan and clean any sludge off of the oil pump pickup tube screen, or else replace the pickup tube. I flushed mine twice in the 15 years I've owned my 2001 Suburban. First time I did it I had to replace the oil pan gasket anyways, so I had no problem with dropping the pan afterwards. I was shocked by the amount of sludge that was dislodged by the flush. All the sludge throughout the engine was loosened up by the flush additive, and it accumulated in the oil pan. I flushed it again nearly 100k miles later, but I made the huge mistake of not dropping the pan this time, I just drained it and poured in fresh oil. A few weeks later, I slipped a camshaft bearing. I lost all oil pressure and THEN I decided to drop the pan and I was horrified by the amount of sludge in the oil pan. It was almost as much as the first flush I did nearly 10 years ago. I thought maybe my oil pump was bad. I cleaned it all up, I installed a new oil pump and still had no pressure. After more diagnosing, I found I had pressure in the front of the engine right at the pump, but no oil was getting to the back of the engine. Every mechanic I spoke with said the exact same thing, that for all that to happen like I describe then I slipped a cam bearing and it's blocking the oil passage. So now I'm in the process of getting a crate engine installed. So I beg of you, don't be stupid like I was. Go ahead and flush it if you want, but just be sure to drop the oil pan afterwards. If you have a 2wd it's actually really easy. It's a little more involved on a 4wd, but it's still doable.