Good question, Erasto. Our standard recommendation is to add it 100-300 miles before you change your oil. That gives it enough time to circulate and clean, and then allows the reliquefied residues and deposits to be drained away with the old oil. 

If you’ve already added it, you can leave High Mileage in the oil crankcase for 1,000 miles before you change your oil. It won’t harm anything and it will work to clean and reliquefy oil residues. 

Good question, Mike!

You’ll first want to get rid of the old gas and oil, and then use Sea Foam High Mileage to clean buildup that formed in the fuel and oil systems while it was sitting.

Here’s what I would do: Start by removing (siphon/drain) as much fuel as possible from the tank. Once the tank is empty, add a can of Sea Foam High Mileage and 2-3 gallons of fresh fuel to the tank. If it starts and runs, run through as much of the fuel as possible so the fresh fuel and Sea Foam mix can clean and flush out the whole fuel system. It will do a great job cleaning out any residues and varnish that formed while the vehicle was sitting.

For the oil, start by changing it right away. Drive about 700 miles on the fresh oil, and add some High Mileage to the oil crankcase (1 oz of High Mileage per quart of oil). After that, drive another 100-300 miles to give it some time to circulate and clean, and change the oil again. From there, you can follow your regularly scheduled oil changes. The High Mileage will help clean up oil residues and deposits.

Good question. Yes, Sea Foam is safe and effective in the oil of a 2004 GMC Savana. I’d use Sea Foam High Mileage as it’s formulated to clean stubborn residues and deposits after years of buildup. Add 1 oz of High Mileage per quart of oil 100-300 miles before your next oil change. Adding High Mileage before every oil change will go a long ways towards keeping the oil system clean and preventing problems caused by buildup.

High Mileage would also work well in the gas tank to prevent or overcome problems caused by a fuel residues and deposits (often, rough idle, loss of power, and lost fuel efficiency are caused by this). 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.

Yes, you can absolutely use Sea Foam Motor Treatment in your 1999 4Runner! 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.

You could also try High Mileage Motor Treatment. It’s made specifically for stubborn residues and deposits in higher-mileage vehicles. It’s a great cleaner!

Thanks for the question, Donald. My recommendation would be to use Sea Foam Spray through the carb and Sea Foam Motor Treatment or High Mileage in the fuel tank. If the engine still has a tendency to idle high sometimes, I’d recommend having a mechanic look at the carb. It would be a simple choke adjustment.