Cleaning Intake Manifolds: Delivering Important Information

Cleaning intake manifolds is essential information to ask in order to maintain the integrity of your car’s engine. Though the most preferable and effective way to clean the intake manifold is to remove the entire manifold, it can be tedious and time-consuming.

Clean an Intake Manifold

This is why many prefer to keep the inlet manifold in place while they clean it. It sounds simple enough but it can also be tricky and that’s why our team will give a few tips on how to get rid of all the carbon build-up in the inlet manifold.

What Are the Best Ways To Clean an Intake Manifold in Its Place?

The best ways to clean an intake manifold in its place are using a throttle body cleaner, an intake manifold cleaner, and sea foam spray. However, these methods are dependent on the type of fuel the engine uses. Using the wrong cleaner on an engine could cause problems.

Intake manifold cleaners are great for diesel engines while sea foam sprays are more efficient in gasoline engines. Throttle body (butterfly valve) cleaners are suitable for gasoline and diesel engines but are the least efficient of the three.

Some of the benefits of cleaning the air intake manifold include an increase in fuel economy, strong engine performance, and prevention of the engine from damage. Regular cleansing of the manifold can prolong the life of the engine while also saving you money.

  • Using a Throttle Body(Butterfly Valve) Cleaner

A butterfly valve cleaner is a degreaser that gets rid of oil, grease, grime, cutting fluid, dirt, fingerprints and other common contaminants. However, it is not designed to remove carbon buildup, but is efficient in cleaning oil grime which is very common in gasoline engines. Using a butterfly valve cleaner is the easiest and cheapest of the three but least effective as explained above.

Using a Throttle Body Cleaner

To use this method, you’ll require a flat screwdriver, clean cloth, toothbrush and a butterfly valve cleaner spray. To get access to the intake manifold also known as the inlet manifold, remove the air intake duct found on top of it. Once the manifold is bare, spray some cleaner on the butterfly which is found between the air intake filter and the manifold.

Wait for about 30 seconds after spraying then clean the grease with a clean cloth. Before the next step, ensure you take note of the position of the inlet manifold when it is closed because it is very important. Now, open the butterfly valve by turning the part where its cable is connected on the outside.

Once it is opened, sprinkle some cleaner on the throttle valve seat, which is the position where the air inlet manifold rests. Remove any grime around the area with a toothbrush and clean it with a cloth and start the engine. Once the engine is running, intermittently sprinkle some cleaner inside with the throttle valve while still closed and remember to use about half of the cleaner.
  • Using an Inlet Manifold Cleaner for Diesel Engines

Diesel engines are more notorious for carbon build-up than gasoline engines, thus they require a much more effective method of intake manifold cleaning. Fortunately, an air inlet manifold cleaner does the job quite well and at a similar price to the butterfly valve cleaner procedure. The entire process is simple and won’t take much of your time, thus it’s worth considering.

Inlet Manifold Cleaner for Diesel Engines

To complete the process, you’ll need a flat screwdriver and an inlet manifold cleaner with its hose attached to it. Start by removing the inlet manifold hose, just as in the first procedure, to get access to the device. Ready the inlet manifold cleaner and start the engine – ensure the engine is running throughout the whole process. Now, insert the cleaner’s hose into the end of the manifold then spray it while slowly removing the hose until the can is empty.

When you notice the engine shaking, briefly pause the spraying until the shaking stops, then resume the spraying. After emptying the cleaner into the inlet manifold, turn off the engine and put back the intake hose you removed in the first step.

You can then take the vehicle for a test drive and try to hit the red line on the speedometer without breaking the speed limit. This should clear out the remaining soot in the manifold. You can check the manifold to see if there’s any dirt and if there is, repeat the process. You may require more than one cleaner depending on the amount of carbon build-up in your manifold.

  • Using a Sea Foam Spray for Gasoline Engines

The best inlet manifold cleaner of the lot is Sea Foam spray, however, it is also the trickiest to use. Sea Foam spray is designed to clean gasoline engines, thus they don’t do well in diesel engines and might even damage them. Note that white smoke might come out of the exhaust pipe during the process of cleaning, but don’t panic, everything is fine. Meanwhile, ensure the engine is running when you’re spraying the cleaner into the manifold to prevent hydro locking.

Sea Foam Spray for Gasoline Engines

First, turn the engine on and allow it to run for a while until it achieves optimum operating temperature, then turn it off. Now, take out the intake hose from the butterfly valve, slip in the red straw and replace the intake hose. Remember to secure the intake hose firmly to prevent vacuum leaks and then start the engine until it reaches 2,000 rpm. Keep the engine running at 2,000 rpm and fix the cleaner to one end of the red straw and start spraying into the manifold until the cleaner is empty.

After spraying, turn off the car and take out the intake hose so that you can remove the red straw, after which you should reinstall the intake hose. Allow the vehicle to sit for 10 minutes, after which you can take it for a test drive during which you should hit the red line. Repeat this several times without crossing the speed limit to ensure all the carbon build up is gone. Note that you’ll need a friend during the process, especially to help you hold the engine speed at 2,000 rpm.

How Do You Clean Intake Manifold With Oven Cleaner

To clean intake manifold with oven cleaner, you have to apply the cleaner to the manifold a total of three times, letting it sit for different times and rinsing with hot water each time. However, be warned that this method is dangerous and not recommended.

Specifically, take note that cleaning the intake manifold with oven cleaner is highly risky and our experts warn against it. Though there is a high chance of success, its effects can be detrimental when it fails. Only resort to this technique when you are sure you can do it properly and will be solely responsible if anything goes wrong.

First, remove the intake hose to access the manifold, and then spray the oven cleaner into the manifold. Wait for 10 minutes after which you rinse the intake manifold with hot water using a water hose. Next, spray the oven cleaner again into the manifold and, this time, let it sit for 30 minutes before rinsing it with hot water. Once again, spray the cleaner into the manifold and leave it overnight.

The next day, rinse the intake manifold with hot water using a water hose with low pressure and your air intake duct should feel brand new. However, be careful to not use oven cleaner on the pistons as it could cause them to lose compression.

Why is Cleaning Intake Manifolds Important for Preventing Oil Buildup?

Cleaning intake manifolds is key in fixing oil in intake manifold and preventing oil buildup. Ongoing oil accumulation can hinder engine performance and cause various issues, such as reduced power and increased emissions. Regular maintenance, including cleaning the intake manifold, helps remove oil residue, dirt, and sludge, ensuring proper airflow and optimal engine function. By preventing oil buildup, this crucial task keeps engines running smoothly and efficiently.


We’ve now equipped you with diverse ways by which you can cleanse your dirty intake manifold without detaching it from the engine.

Here is a summary of the most important points to take away:

  • There are three ways you can clean the intake manifold of your engine without removing it, which are using a butterfly valve cleaner, using an intake manifold cleaner, and using sea foam spray.
  • The butterfly valve cleaner is the least effective and the cheapest way of cleaning the manifold, though it doesn’t get a lot of carbon build up.
  • Using the intake cleaner is best for diesel engines as it does an excellent job of cleaning carbon build-up, a major problem associated with diesel engines.
  • The Sea Foam spray is the trickiest to use and you’ll need a friend to help you with the entire process, however, it efficiently cleans the inlet manifold of gasoline engines.
  • You can also use an oven cleaner to dissolve all soot inside the manifold but ensure that it doesn’t touch the pistons or it could damage them.

Whatever method you use, make sure you follow the guidelines religiously and ensure that you don’t use cleaners suited to diesel engines for gasoline ones. Ensure you clean the air intake manifold regularly to keep in the engine in prime condition and to prolong its life.

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