Thanks for the question!

Yes, you can use Sea Foam Motor Treatment in the fuel tank and oil of a Mercedes diesel. Just follow the directions on the can.

Note that Sea Foam is NOT for use in a DEF system. Do not add it to the DEF tank.

Thanks for the question!

Yes, Sea Foam products are compatible with older, carbureted vehicles like your GMC. Both Trans Tune and Motor Treatment don’t contain harsh chemicals and are made with petroleum ingredients that can’t harm engine parts or components.

I’d recommend using Sea Foam High Mileage in the gas tank of your GMC. It’s a strong cleaner. For a cleaning dosage, wait until you have a low tank of fuel (1/8 tank or so), add 2 cans of High Mileage, and drive at least 20 miles (until almost empty) before you refuel. The high concentration works very well to clean fuel residues and deposits.

In your transmission, just follow the directions on the Trans Tune can.

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

Adding Sea Foam to each tank wouldn’t hurt. The Sea Foam would prevent fuel residues and varnish from forming, which will keep your generator free from problems that residue and varnish causes (hard starts, rough performance, etc.). Add at least 1 ounce of Sea Foam per gallon of fuel to every tank. That would be a good addition to your preventative maintenance routine. It’s a good idea to run it monthly as well.

Thanks for the question, Bob.

Sea Foam will clean any residues and varnish from the old fuel. It’s best practice to drain any old fuel (or run it to use it up), and then add 16 oz of fresh gas with 8 oz of Sea Foam (or whatever amount of fuel you’d like with a 2:1 ratio). That will create a strong cleaning concentration and work very well to clean up the entire fuel system. After that, add 1 ounce of Sea Foam per gallon of fuel to prevent it from degrading when it’s sitting.

Hi Tom,

Thanks for the question! No, Sea Foam in your gas tank won’t harm your catalytic converter. (It won’t clean it, either, which is another question we get often).

Tip: to get the most out of a can of Sea Foam, consider using a high cleaning concentration. 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.