Does Sea Foam Really Make a Difference?


Sea Foam is a product that has been around forever. It originally began in the 1930s as a fuel additive to prevent carbon buildup in 2-stroke outboard motors in fishing boats.

People ask us all the time, “does Sea Foam really make a difference?” The reason this question comes up is that modern engines run much cleaner with less carbon build up.

Sea Foam Motor Treatment has many different uses, as we discuss below. However, the short answer is that customers give Sea Foam very good reviews (at about a 4 to 1 ratio) and believe it helps.

Is it worth the money? That depends on your situation. We generally recommend people try a fuel additive 1-2 times to see how it works for their car and particular circumstances.

What is Sea Foam?

Sea Foam has several products. The one we will be discussing and the one most commonly used by everyday drivers is called Sea Foam Motor Treatment.  

Does Seafoam Really Work

It is a 100% petroleum fuel additive that has several advertised purposes:

  • Cleans injectors
  • Cleans carb jets
  • Stabilizes fuels
  • Controls moisture levels in fuels
  • Quietens lifters
  • Adds lubrication
  • Cleans (carbon) deposits
  • De-ices and anti-gels fuels.

How to Use Sea Foam?

As far as automotive products go, Sea Foam is blessedly simple to use. Literally just pour the contents into the fuel tank. For some newer vehicles a funnel will be required.

Pro tip: these are often provided by manufacturers. Mine was included in the spare tire insert, so double check before purchasing one.

The only real challenge is getting the “dosage” correct. Sea Foam recommends the following:

  • For regular fuel system maintenance use 1 ounce per gallon of fuel in your tank. To visualize this, 1 ounce = 2 tablespoons.
  • For periodic cleaning, use 2 ounces per gallon of fuel.

Want the good news? Even if you put in too much, there is no real downside other than cost. Your engine will be perfectly fine. It may just be a little bit extra clean.

Does Sea Foam Really Make a Difference?

When asked this question, “at what” is the appropriate reply. Remember, Sea Foam claims to do many things. After reviewing government studies, tons of customer feedback and any literature we could find, here is our take.

Does Sea Foam Improve MPG?

No, not directly at least. The government conducted a study of 30 leading additives and found no direct increase in miles per gallon. 

There MAY be indirect increases though. If your car has carbon buildup and is not running optimally, a cleaner engine will likely get better miles per gallon. It would, however, take time and multiple treatments.

Does Sea Foam Really Make a Difference When Storing Your Vehicle?

Yes. If you do not start your engine frequently, moisture and condensation can destabilize the fuel. In our experience, Seafoam is very good at maintaining fuel viability. This is doubly true in extreme cold weather environments.

Does Sea Foam Help Clean Your Car’s Engine?

Yes, although this is highly debated, and opinions can be found all across the spectrum. Here’s what we know. Actual buyers give it overwhelmingly great feedback, with positive reviews outweighing the negative 4 to 1. Most experts agree that it won’t hurt your engine and certainly could help if you have carbon buildup.

Here is an example of DIY tester that shows Sea Foam reducing carbon buildup in the pistons.

Our view is generally favorable, especially if you have an older car. Many users will add Sea Foam Motor Treatment to their gas tank every time they change their oil. It doesn’t have to be done in conjunction with an oil change, rather the timing just serves as a helpful reminder.


Sea Foam is a product that has been around since before World War II. It has about as long of a track record as you will find among automotive products.

If you don’t use your car that frequently, we definitely recommend using Sea Foam Motor Treatment. Also, if you have concerns about carbon buildup in your engine, using Sea Foam a few times and checking the results is a good strategy.

If you are trying to improve gas mileage quickly, there are other actions that will yield quicker results. See our article on how to get better gas mileage.

Given the right circumstances, Sea Foam Motor Treatment is definitely worth checking out.

Sea Foam Motor Treatment - Pack of 2
  • Dissolves and clean fuel deposits and sticky residues from gas and diesel fuel injectors, carburetors, and combustion chambers
  • Package dimensions :5.0" L x5.0" W x8.25" H
  • Does NOT have harsh detergent or abrasive chemicals that can harm your engine
  • Country of origin :United States






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