As the title says ... I am planning to do some Seafoaming of my car over the Thanksgiving weekend. I'm going to be doing Seafoam in the gas tank and the crank case. Gas tank I'm going to add it when I top off before the trip and run it the approx 290 miles north (and then change the fuel filter) ... but I seem to recall reading that it shouldn't be left too long in the crank case. Any thoughts?