I used seafoam years ago on a high mileage car I had just bought. I did it slightly different, starting with pulling the plugs and pouring a little on top of each piston and letting that sit for 5 or 10 minutes. Then I did the 1/3 in the gas tank, 1/3 in the crank case, 1/3 through a vacuum hose while running. White smoke was billowing out the tail pipe, huge clouds of stuff. Once the half tank or so of gas was was down to E a couple days later I changed the oil. It made a difference, the engine ran smoother after all that.
Now I just run a can of techron through the engine once a year and try to stick with Tier 1 gas (Chevron if it's convenient), but if I buy another high mileage car I'll probably seafoam it.
Now I just run a can of techron through the engine once a year and try to stick with Tier 1 gas (Chevron if it's convenient), but if I buy another high mileage car I'll probably seafoam it.