how to use Sea Foam

How To Use Sea Foam: Three Ways To A Cleaner Fuel System

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Over time, the internals of your engine get clogged up with all kinds of nasty stuff. Inside the crankcase, where the oil lives, varnish and tar build up on the surfaces of the pistons, rings, lifters and in the oil galleys that supply the oil to all the components. This lowers the engine’s ability to cool and lubricate itself, reducing the efficiency, performance, and life of the engine.

The same build up occurs inside the fuel system as well, clogging the injectors or carburetor jets, gumming up the intake valves and on the tops of the pistons too. If the valves don’t move freely, then your engine’s breathing is greatly hampered. Carbon deposits on the pistons and valves can lead to hot spots which cause detonation, which lowers your engine’s performance. The trick is how do you clean? Virtually every engine, from 2-stroke lawnmowers to big rig diesels face the same problem.

Cleaner Is Better

Sea Foam has been around for over 70 years, and it is one of the most trusted treatments for all engines. While Sea Foam makes a range of excellent products, the main one is Sea Foam Motor Treatment. Sea Foam is specially formulated to safely and slowly re-liquify the gum, sludge, varnish and carbon deposits from the hard parts in your engine so they can be flushed out of the system.

Sea Foam helps lubricate the moving parts, particularly in the fuel system. Ethanol additives dry out the seals and leaves a varnish that makes it harder for oil to lubricate the parts. Removing this varnish brings the engine back into top working order. Inside the fuel tank, Sea Foam absorbs water, allowing it to be burned up in the combustion chamber without issue.

How To Use Sea Foam

When deciding how to use Sea Foam Motor Treatment there are three options: in the crankcase, in the fuel tank, and in the diesel fuel filter. For cleaning the top end, use Sea Foam Spray as directed.

In The Crankcase

When added to the oil, Sea Foam will clean up sludge, quiet noisy lifters, and remove oil varnish. One can treats 16 quarts of oil so you get 2 treatments in one can for most vehicles. The best method is to add the treatment 500-1,000 miles before the next oil change, and then add the rest after you have changed the oil. This will get the big amounts of varnish and sludge out, and the second treatment keeps things clean.


Pop the cap on the oil filler neck. You can add Sea Foam before or after an oil change.

Pop the cap on the oil filler neck. You can add Sea Foam before or after an oil change.


Pour up to 1 ounce of Sea Foam per quart of oil into the engine. We used about ½ of the bottle.

Pour up to 1 ounce of Sea Foam per quart of oil into the engine. We used about ½ of the bottle.

In The Fuel Tank

One can treats up to 16 gallons of fuel. This will remove deposits from the fuel pump, injectors or carb jets, control moisture, and stabilize the fuel. In diesel engines, it will de-ice and has anti-gel properties.

One bottle treats up to 16 gallons of fuel. We poured in 1/2 of the bottle to make this a one-bottle job.

One bottle treats up to 16 gallons of fuel. We poured in 1/2 of the bottle to make this a one-bottle job.

On The Top-End

To clean carbon deposits from air intake systems, intake valves and combustion chambers inside the engine, including GDI engines, Sea Foam recommends using Sea Foam Spray Top Engine cleaner and lube (Part # SS-14). Sea Foam Spray is the same great Sea Foam only in aerosol spray instead of liquid form. Sea Foam Spray is used by inserting the included application hose and patented “HOOK TOOL” into the air intake just in front of the throttle plates in the throttle body.  Then start engine and let it warm up to operating temperature. Increase idle speed to 2,000 RPM and spray the contents of the container into the engine. Shut the engine off and allow it to “Hot Soak” for 15 minutes. After the Hot Soak period restart the engine and road test the vehicle aggressively until the exhaust is clean (road test normally takes 5 to 10 miles of driving). Easy to follow directions are also available right on the Sea Foam Spray container.

Treatments like this may seem complicated, but with a little bit of prep work, you can do it yourself and restore your vehicle’s power and performance. If you have any concerns, stop by your local NAPA Auto Parts Store or NAPA AutoCare Center.

Sea Foam Spray Top Engine cleaner and lube

Check out all the chemical products available on NAPA Online or trust one of our 17,000 NAPA AutoCare locations for routine maintenance and repairs. For more information on how to use Sea Foam Motor Treatment, chat with a knowledgeable expert at your local NAPA AUTO PARTS store.

about author

Jefferson Bryant

A life-long gearhead, Jefferson Bryant spends more time in the shop than anywhere else. His career began in the car audio industry as a shop manager, eventually working his way into a position at Rockford Fosgate as a product designer. In 2003, he began writing tech articles for magazines, and has been working as an automotive journalist ever since. His work has been featured in Car Craft, Hot Rod, Rod & Custom, Truckin’, Mopar Muscle, and many more. Jefferson has also written 4 books and produced countless videos. Jefferson operates Red Dirt Rodz, his personal garage studio, where all of his magazine articles and tech videos are produced.

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  • Bill Bock

    October 6, 2016 at 11:48 PM


    Use Seafoam In All My Vehicles…Motorcycles ,Cars ,Trucks ,Lawn Mowers, Etc…Excellent Product…Been Using For 5yrs …Keeps Everything Running Smooth 🙂

  • Pat Mooney

    January 2, 2017 at 4:18 PM


    Should I put seafoam in gas tank before or after fueling up?

    • Brian Medford

      June 2, 2017 at 12:22 PM



  • Marvin Conner

    March 8, 2017 at 6:22 PM


    The number one killer of $130k funeral vehicles is lack of use. What I mean is we never get a chance to run them out on the open hwy. they have mufflers rust out at 8k because they never get hot enough to purge the moisture out. Funeral home to church is about 10 slow minutes. Then a slow crawl to the cemetery for 20 25 minutes, always shutting the engine off at every destination. Then going back to the funeral home in slow city traffic and back into the garage. Our new state of the art Cadillac hearse costs more than my house. I asked our mechanic at the Cadillac dealership about sea foam and he said it could void the warranty on emissions and just keep coming in for the $200 de carbon treatment. Bull! We bought six cans and on a Sunday night (closed) treated all of our six vehicle fleet. Then did a convoy down I 95 at highway speed. The results were amazing ! Our two 2006 hearses belched black then white smoke like a fire. We now take all the fleet out for a pizza and beer run down the interstate for a 60 mile round trip. We told the other mortuaries about this on the blog.

  • Twins Fan

    June 3, 2017 at 8:02 AM


    My spouse and I rented a boat at a mom and pop fishing resort that was in disrepair, as was the boat they provided. After sitting all winter with ethanol fuel in the carb, the little 2 stroke outboard barely ran without the choke engaged, and never ran at all at full throttle. Knowing about Seafoam, we topped off the small gas tank with a can of Seafoam (over kill on the mix I suppose, but it worked wonders). After a few hours of fishing , the engine ran better than it probably had in years. Seafoam is one of the “snake oils” that actually works.

  • Minorkle

    July 3, 2017 at 2:29 PM


    I will try it in my hearse

  • Russ

    August 6, 2017 at 1:13 PM


    I had a P0013 code, CAM position sensor on my 2012 Equinox and I could not get rid of. The dealer replaced the sensor (maybe!) and it left for a while and came back. I finally added 4 oz of SeaFoam into the crankcase and BAMM, it is gone! Thanks!

  • David A Stojke

    November 27, 2017 at 11:16 AM


    Miracle stuff, imo….Have an old Roadrunner that sat for awhile. Didn’t want to run…My brother told me about Seafoam. I’d never heard of it before even though I’d been quite a bit of a motorhead my whole life…Dupped a can in the tank and the car ran. Later, I rebuilt the carb, which it needed badly. I couldn’t believe how bad the carb was, and really couldn’t believe Seafoam even made it run! I’ve believed in the stuff ever since….I recently got a 04 Grand Cherokee with a bit of a tick in the valve train. I will put some Seafoam in the crankcase and see what happens. I’ve never used it in a crankcase before, so this will be interesting. I have high hopes!


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