Thanks for the question!

I’d add a whole 16 ounce can to a half tank of fuel. That said, here’s my recommendation in general: wait until the tank is low (1/4 -1/8 tank), and add a whole 16 oz can of Sea Foam. Then, drive until almost empty before refueling. The high concentration of Sea Foam will work very well to clean critical engine areas. Rather than adding it to a full tank, it works better and faster to use a whole can in a low tank of fuel.

Thanks for the question, Raymond. Sea Foam does not have a lifespan – you can definitely still use a can that’s two or three years old!

Yes, Sea Foam Motor Treatment is safe and effective in your 2018 BMW Gran Coupe. Just follow the instructions on the can.

Here’s a little more info on how to use it:

• Sea Foam Motor Treatment in fuel. I like to wait until the tank is low (1/4 -1/8 tank), add the whole 16 oz can, and then drive for at least 10-20 miles before refueling. It’s safe to add a high concentration like that and it works very well for cleaning fuel residues and deposits.
• Sea Foam Motor Treatment in oil. Add 1 ounce of Sea Foam per quart of oil in the crankcase. We recommend adding it 100-300 miles before your next oil change. That gives the Sea Foam enough time to circulate and clean, and it allows all the reliquefied oil residues to be drained away with the old oil.

Good question, Tom. If the surging is caused by gum or varnish anywhere in the fuel system, Sea Foam will clean it up and help it run better.

Adding a high concentration like you mentioned will be the best way to use it. Add the Sea Foam, run it for a few minutes to draw the treated fuel through the fuel system, and let it sit overnight. Start it up the next day and run it for a while. You would not have to remove the jet as the Sea Foam would clean it up as the treated fuel goes through.

Thanks for the question! The best practice for fuel that’s been sitting like that is to drain it. Fresh fuel will have better volatility for starting and won’t have any gum or varnish. However, you could add some Sea Foam and give it a shot if the fuel is only 6 months old. Your goal will be to draw enough treated fuel into the fuel system to clean up the jets, let it sit overnight, and then run it again the next day.

Whether you drain it or not, add a full 16oz can of Sea Foam to a low volume (about 1 gallon) of fuel. Then, run it for a few minutes to get the treated fuel into the fuel system. Let it sit overnight, and start it up the next day and let it run for a while.