I would run sea foam for 100 km and change the oil. It works. The instructions are different. They want you to warm the engine and the dump in the product and only idol for 15 min. I found leaving it in for a day or so. Depending on driving habits the change oil. I put it in on a Friday and drive to work and shopping Saturday then change oil Saturday afternoon when it's still hot or Sunday. After warming up the truck. Then synthetic oil of choice. Try it you will be surprised on the difference.
It also works on small engines.
Yea I Just Put A Bottle Of Sea Foam In The Gas Tank. I'm Gonna Put Some In The Crank About A Day Or So Before I Change It. I Tried Synthetic Once On My Truck But Didn't Really Feel A Difference. I Also Heard To Try Adding Zinc Since All Motor Oils Besides Valvoline Have Eliminated It From Their Oil