How to Use Seafoam

Last Updated: February 8, 2022 References

Seafoam serves a variety of automotive purposes. You can use it to remove buildup in the engine, fuel injectors, or oil system. Make sure that you know how much to add, though, since adding too much can cause more harm than good.

Method 1

Method 1 of 3:

Engine Cleanser

1
Warm up the engine. Park the car in a well-ventilated area and start the engine. Let the engine warm to operating temperatures.
- You must do this while the car is in a well-ventilated area since the process will usually create a lot of smoke.
- Vehicles with automatic transmission should be kept in park. Vehicles with manual transmissions should be put into neutral, and the parking brake should be applied throughout the process.
2
Locate a vacuum line. Open the hood of the car and locate a vacuum line that distributes evenly to all cylinders of the engine.
- On most vehicles, the best option will be the vacuum line from the brake booster PCV.
- Since different vehicles are set up in different ways, you may need to choose a different option. If in doubt, seek a professional opinion before attempting this method.
Advertisement
3
Disconnect the hose. Carefully disconnect one end of the selected vacuum hose.
- If using the brake booster hose, disconnect the hose going to the manifold. The check valve should remain on the hose going to the brake booster, and you should not allow Seafoam to pass through the check valve during this process.
4
Slowly pour Seafoam into the vacuum hose. Carefully pour one-third to one-half of the bottle directly into the detached hose.^{[1]
X
Research source}
- If necessary, position a funnel in the opening of the hose and pour the Seafoam in through that.
- The manufacturer recommends against the practice of drawing Seafoam into the hose using suction.
5
Rev the engine simultaneously.^{[2]
X
Research source} While you pour the Seafoam into the vacuum hose, a second person should rev the engine up to 2000 RPM.
- You will probably see heavy white smoke coming out of the tailpipe. This is normal and should not be cause for alarm.
6
Let the engine sit. As soon as you finish pouring Seafoam into the vacuum hose, turn off the engine and allow the car to sit for 10 to 30 minutes.
- The longer you wait, the deeper the Seafoam will sink into the engine. Regularly maintained engines may only need a 10-minute wait, but for engines with a lot of suspected buildup, a full 30-minute wait would be better.
7
Drive until the smoke clears. Start the vehicle again and drive aggressively for five to ten minutes, or until your tailpipe stops pumping out heavy white smoke.
- Drive legally. If possible, go on a road where you can reach speeds up to 60 MPH (97 km/h). This is best done at night or during another time when traffic won't be an issue since your tailpipe will produce a lot of smoke.
- Once the smoke stops, the engine is clean and the process is complete.

Method 2

Method 2 of 3:

Fuel Injector Cleanser

1
Figure out how much Seafoam you'll need. Find out how many gallons of fuel your vehicle's fuel tank holds. For each 1 gallon (4 L) of fuel, you will need to add 1 oz (30 ml) of Seafoam.^{[3]
X
Research source}
- Adding Seafoam directly to the fuel tank will provide a variety of benefits. It can clean deposits left behind in the fuel injectors, thereby making your vehicle run more smoothly. It can also control moisture buildup in the fuel, stabilize the fuel, and lubricate the upper cylinders.
2
Fill the gas tank. Go to the gas station and fill the vehicle's gas tank with high octane gasoline.
- When filling the tank, make sure that you leave enough room in the tank to add the calculated amount of Seafoam afterward.
- While Seafoam can technically be used with any octane gas, it is recommended that you use it with 91 octane or higher. Fuel with a higher octane number requires a greater amount of heat and compression to ignite, leading to improved performance. The Seafoam can provide a greater benefit to the vehicle under these conditions, as well.
3
Pour the Seafoam into the fuel tank. Place a long-neck funnel in the fuel tank and pour your calculated amount of Seafoam directly into the fuel tank.^{[4]
X
Research source}
- Pour the product slowly to avoid spills.
- Using a funnel will also help prevent spills. Due to the design of the bottle and the position of the fuel tank opening, it is nearly impossible to pour Seafoam directly from the bottle and into the fuel tank without the use of a funnel.
4
Drive the vehicle. Put the fuel tank cap back on and drive your car at a steady pace for at least five to ten minutes.
- As you drive, the Seafoam should mix into the gasoline, improving the quality of the gasoline and cleaning the fuel injectors at the same time.
- Try to run this tank of gasoline until the vehicle is nearly empty to maximize the effectiveness of the Seafoam.
- After completing this step, the process is complete.

Method 3

Method 3 of 3:

Oil System Cleanser

1
Calculate the correct amount of Seafoam. You will need to use 2 oz (60 ml) of Seafoam for every 1 gallon (4 L) of petroleum oil.^{[5]
X
Research source}
- You'll be adding the Seafoam directly to the oil in your vehicle. Since Seafoam is made of petroleum, it is safe to mix into the oil and should not cause any damage to the vehicle.
- When used in this manner, Seafoam will re-liquify old fuel and deposits, clearing out the carburetor bowl and jets in the process.
2
Keep the engine cold. Switch off the engine, if it is presently running, and allow the engine to completely cool down before continuing.
- Adding room temperature Seafoam to burning hot oil can shock the carburetor valve springs and damage your vehicle.
3
Pour Seafoam into the carburetor throat. Remove the cap from the engine oil spout and pour the calculated amount of Seafoam directly into the carburetor throat.
- Consider using a funnel to pour in the Seafoam. Doing so is not strictly necessary, but funnels can help reduce the threat of accidental spills.
4
Drive the vehicle as many as 250 miles (402 km). Cap the carburetor throat, close the hood of the car, and drive the vehicle as usual for as many as 250 miles (402 km).
- You should get the oil changed once you have driven a distance between 100 and 250 miles (160 and 402 km). Seafoam is a potent additive, so the oil filter can struggle and the quality of the oil can degrade after this distance.
- After driving the car and changing the oil, the process is complete.

Community Q&A

Question

Will the second method cause smoke?

Community Answer

No, not if you use the correct amount.
Question

How will pouring seafoam in my gas tank help with the ticking from my lifters?

Community Answer

It probably won't. You're better off doing the vacuum line or oil treatment to go after the lifters, but even then you're probably better off having the lifters physically inspected, cleaned, and/or replaced.
Question

My car does not have a carburetor. Where do I pour the seafoam?

Community Answer

You can pour a little bit into the intake while it's running, along with the gas tank. If you want to get seafoam into the cylinders, it needs to be either in the air or the gas on your fuel-injected vehicle.