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Is Seafoam Good For Your Engine?

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Seafoam bottle being held up against a car engine of an Infiniti J30 in the background

In an effort to extend the life of their vehicle, a lot of people turn to seafoam. They’ll add it right into their fuel tank, add it alongside their oil, and spray it into their air intake. While it might sound absurd to add to an engine, you’re probably wondering if seafoam is good for your engine.

Seafoam works really well at lubricating, unblocking, and extending the life of your engine. People add it at regular intervals in an effort to make the engine last longer by removing any carbon buildup. Seafoam is good for your engine. Since it uses largely organic matter, it’s safe to use on your car and safe to handle.

This short guide will answer that question and more. I’ll explain what seafoam is, what it does, my experience with it, and some benefits of using it on your vehicle.

What Is Seafoam?

Seafoam is the foamy white and yellow stuff you might see at the beach. It looks like clouds that go in and out with the tide.

It’s made up of decaying algae and different organic matter.

Seafoam is also used in a line of car cleaning products called Sea Foam (note the capitalization). Sea Foam is used to clean, lubricate, and protect the internal systems of your car.

People use Sea Foam in their gas tanks, oil reservoir, and air intake system. Throughout this guide, I’ll be talking about seafoam in general, and the specific line of Sea Foam products interchangeably.

Sea Foam SF16 Motor Treatment 16 oz.

Sea Foam SF-16 Motor Treatment Multi-Use, 16 oz.

The History of Sea Foam and Cars

Seafoam and cars might seem like such a random pairing. It’s certainly strange, but it dates back to the early 1940s. Back then, a fisherman was mad that his outboard motor kept breaking down. He tried a few mixtures, and ultimately landed on one that used seafoam.

Today’s mixture contains a variety of different organic materials like plankton, seafoam, algae, fungi, and plant detritus.

It helped his engine so much that he started sharing it with his fishermen friends who kept spreading the word and demanding more. Eventually, it evolved into the brand Sea Foam, with a focus on motor treatment.

Whenever something works well for a boat motor, it’s typically tried on a car engine. The results were the same, and since then people have sworn that seafoam in a car’s engine is a game-changer.

Why People Choose Seafoam

There are a lot of engine cleaners and lubricants, so why do people choose seafoam? Based on conversations I’ve had in the past, it’s because the product is very natural and doesn’t include abrasive chemicals like other cleaners.

With more harsh products, it’s easy to abuse them and wind up doing damage to your vehicle. A product like Sea Foam, on the other hand, can be used much more often without the same negative effects.

The reason why I’ve used seafoam in the past is that the product is easy to work with and not as scary as other cleaners. I used an engine cleaner one time that said multiple times on the bottle to never handle it with bare skin. That scared me enough to look for alternatives, and that’s how I first stumbled on seafoam products.

Since it’s mostly made of natural and biological components, the risk is much lower.

Where to Put Seafoam in Your Car

Seafoam enthusiasts target three different areas to apply seafoam. All three locations aim to clean different parts of your vehicle’s internal systems.

In the Fuel Tank

The most popular is probably in the fuel tank. There is a Sea Foam product that pours directly into your fuel tank and mixes with the gas. From there, it will work in the background.

In the meantime, your fuel pump and injectors will get cleaned. The moisture level will be optimized, and the fuel will be stabilized.

I’ve done this in the past, and the process was easy. The container tells you how many gallons of fuel it will work for. The one I used was good for 15 gallons, so I would add it every time I filled up my tank. I would fill up at a gas station, then when I got home, I would pour a container of this Sea Foam product directly into the gas tank.

Holding up a bottle of SeaFoam motor treatment near a fuel tank of an Infiniti J30

Add it with Oil

Another way to get Sea Foam in your car is to mix it with your oil. In this case, you’ll clean out the internals of your engine and remove any sludge buildup that could be slowing you down.

You’ll have to read the bottle, but you add roughly half a bottle to your oil reservoir 1500 miles before your oil change. Right after an oil change, you put in the rest of the bottle.

It only needs to be added in at every other oil change, but it doesn’t hurt to do it every single oil change (so you don’t forget).

It’s safer to do it while your engine is cool, that way you don’t risk burning your hands when you accidentally touch something.

You can use any regular funnel or oil spout that you normally use to add motor oil to the engine.

Seafoam bottle being poured into the crankcase oil hole of an engine block
SeaFoam motor treatment being poured into the crankcase oil hole on a ’93 Infiniti J30

Sprayed in the Intake

Finally, you can also spray Sea Foam in the intake of your car. Doing this will clean the whole intake system and get rid of any debris or buildup along the walls.

To do this, you’ll need the aerosol product line from Sea Foam. With a cold engine, reach into the air intake and spray right in front of the throttle plates.

Afterward, turn on the car and let it idle for a few minutes until the car gets up to temperature. Shut off the engine and spray another generous amount in the same area. Wait 15 minutes then turn on your car and go for a cruise around the block for at least 10 minutes.

Some people also spray the outside of the engine, but I personally don’t understand the appeal of doing that.

Is Seafoam Good for Your Engine?

It might be hard to believe, but seafoam is actually great for your engine. It does a good job of lubricating, de-icing, removing buildup, getting rid of debris, and cleaning the internal systems of your car.

I can’t understand how seafoam products can be so great for your car when they don’t have any detergents or intense chemicals, but it really works. I’m not sponsored by Sea Foam, I’m just genuinely impressed with how well the product works.

It works in cars, lawn equipment, and boat motors alike.

Close up view of the car engine valves covered in soot deposit
Close-up of dirty valves inside a car engine block

How Often To Apply Seafoam

I would refer to the bottle of seafoam that you’re using if you want to know how often to apply it. From a technical standpoint, there’s nothing wrong with overusing the product.

As I mentioned, the fuel additive Sea Foam that I used, was applied every time I filled up my tank. I also know that certain oil-additive Sea Foam products suggest that you use it every other oil change.

Seafoam also makes a high-mileage variant which is best suited for engines that have a heavier more stubborn carbon residue buildup inside.

Your best bet is to pick up a bottle and carefully follow its instructions.

Benefits of Seafoam

There are a lot of benefits of seafoam in your engine, as you probably noticed by now. Let me take a second to detail some of the bigger reasons why you should use seafoam in your engine.

Two SeaFoam bottles side by side high mileage and regular motor treatment bottles on parking lot

Keeps Your Fuel System Clean

Over time, it’s common for debris to build up along the walls of your fuel system. All of the mechanical parts will start to slow down and malfunction once there’s enough buildup.

Seafoam will break down the buildup and clear up the fuel system. A cleaner fuel system means better performance and fuel efficiency.

Inexpensive Cleaning Option

Another reason to mention is that Sea Foam is surprisingly inexpensive for how well it works. It’s one of those products that I suggest trying because you risk so little since it’s so affordable.

Other industrial-grade cleaners can get pretty expensive.

Safe to Use

Speaking of other cleaners, Sea Foam is one of the safest ways to clean and lubricate your engine. Automotive cleaners often contain toxic chemicals and abrasive compounds. This makes them unsafe to handle and dangerous to overuse in your car.

Lubricates Cylinders

Not only does seafoam clean and unblock your engine, but it also further lubricates your cylinders. When it’s added to your oil, your oil starts working overtime. Lubrication within your engine extends the life of the engine, prevents breakdowns, and results in better performance.

Safe for Any Engine Type

Regardless of your engine type, you can apply seafoam and start seeing results. It works for diesel and gasoline-based vehicles of various engine sizes and valve configurations.

Close up of the back of the SeaFoam motor treatment bottle with instructions visible

Finding the Best Seafoam Treatment

Currently, Sea Foam has over a dozen products they offer. I would suggest starting with their site and reading more about them. I used the Sea Foam High Mileage back in the day (and I just ordered another bottle today to start that habit up again).

You can also check the shelves at your local Advanced Auto Parts or AutoZone, which are both approved suppliers of Sea Foam.

Start with a single bottle and get more if you like the results.

Frequently Asked Questions (FAQ)

Q: Is seafoam dangerous for older cars?

A: Seafoam is not dangerous for older cars. It won’t save an engine that’s already failing, but it will slow the degradation process by cleaning the inside of an engine from any carbon buildup that accumulates over the years.

Q: Which Sea Foam products should you use?

A: Their site has its full lineup with detailed instructions for each product and the recommended usage.

Q: Does seafoam void your car’s warranty?

A: No, seafoam is just a cleaner, additive, and lubricant. Your car’s warranty will still be intact after using seafoam.


Now you know more about seafoam and Sea Foam. It’s a product that I’m happy I stumbled across, and it has a lot of great benefits — it will lubricate your engine, help your car last longer, and unblock the internals of your vehicle. Give it a try and leave a comment below to let me know how you liked it.

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Ernest Martynyuk

An automotive enthusiast who's been tinkering with vehicles since I was 15-years old. Repairing automotive electronics has been my main job for over a decade now and have a passion for everything technical regarding cars.

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