Hi Louis,

Yes, you can add it to less than half a tank of gas. In fact, adding a full 16 oz can to a low tank is a very efficient and effective way to use Sea Foam. 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. Add it to fuel like this every 3,000 miles or once a year.

Thanks for the question, Al.

It’s better to add a full can to a low tank of 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. Add it to fuel like this every 3,000 miles or once a year.

Thanks for the question. It depends on whether you’re adding it for preventative/routine maintenance, or cleaning.

For preventative maintenance, add 1 ounce of Sea Foam per gallon of fuel. Guys who add it to every tank as preventative maintenance follow this ratio.

For occasional cleaning, add a high concentration of Sea Foam to a low tank of fuel – about 4 oz of Sea Foam per gallon of fuel. Adding 2-3 cans of Sea Foam to a low tank of fuel is a good way to use it in an excavator like yours. Do that about once a year.

Additionally, here’s a page on our site with some ideas for diesel applications: https://seafoamworks.com/diesel-engine-maintenance-basics/

Thanks for the question.

With 6 year old fuel, I would go ahead and drain it before adding Sea Foam. Here’s an excerpt from our page on starting a car that’s been sitting for a long while:

Gummy varnish and deposits are a common cause of problems like rough idle, loss of power, or poor fuel efficiency in a car that’s been sitting. Adding a high concentration of Sea Foam Motor Treatment or Sea Foam High Mileage to the fuel tank is an easy way to clean fuel residues and deposits from the entire fuel system. If your engine has been sitting for a long time, here are three steps to get it cleaned up and running well again with Sea Foam:

• Start by draining or syphoning the old fuel from the tank.
• Add 2-3 gallons of fresh fuel and a can of Sea Foam High Mileage to the fuel tank. If you can’t drain all the fuel, you’ll still want to add some fresh fuel to bring back fuel volatility.
• Drive until almost empty (at least twenty miles if possible) before refueling with fresh fuel.

You can read the full article here: https://seafoamworks.com/starting-a-car-thats-been-sitting/

Let me know if you have any questions – happy to help!