fuelsome bottles say to use every 3000 miles, but then under it, it will say good to use after every fill up. Which one is it, for fuel injector cleaner?oilcan i use Marvel Mystery oil in between oil changes to top off a bit? Is this ok, or do I have to drain in soon like seafoam. Also if I overfill the oil, what will happen?thanks
fuel. a lot of what the bottle says are advertising. Best advice is to use whatever you want, every oil change. you can use marvel mystery oil in the gas, I do this and have had fine results. Use 4oz per tank of gas. for oil, you can use marvel in the oil and can leave it in. I've used seafoam and have left in the oil long term, like 1000 miles, never have had an issue, with it. You really don't need to worry about oil additives as much, but whatever you do never use the flush stuff, it's kerosene and will cause more harm than good. as for overfilling, you can overfill 1 quart in most cases and be pretty much fine. Usually what can happen is the oil can begin to foam/aerate and the oil pump will pickup oil blended with air vs. straight oil.
It means use the injector cleaner every 3000 miles but after you have filled your tank, Using oil additives in used oil is a waste of time. Most if not all manufacturers frown on the use of additives and their use will invalidate the warranty. Personally I think that they're a complete waste of time and money (42 years experience)
for your injector cleaner, it is safe to use every tank but it's redundant. every 10,000 miles is probably often enough, much less every three thousand miles. For your oil, the mystery oil is safe as long as you are using it in relatively small doses. Most oil additives are very thick, and will cause your oils viscosity to rise, so you're in the clear as long as you aren't using too much of it.
