How to Remove Carbon Buildup in Intake Manifold

How to Remove Carbon Buildup in Intake Manifold – The intake manifold is that component of your vehicle that supplies the air/fuel mixture to the cylinders. It ensures that this air/fuel mixture is evenly distributed into the cylinders to facilitate the first stroke of the combustion process.

The intake manifold is an essential component of a vehicle as it also serves as a cooling mechanism to the cylinders to prevent them from overheating.

The intake manifold can become contaminated by gasoline, oil, coolants, and carbon buildup which can hinder its efficiency.

A common contaminant of the intake manifold is a carbon buildup. 

Carbon buildup is the accumulation of carbon deposits in an engine as a result of incomplete combustion, poor fuel quality, or unavailability of oil in the engine. 

Regular maintenance is important for the optimum performance of your car. This maintenance will help remove carbon buildup on your intake manifold, which will, in turn, enhance the performance of your vehicle.

What is the Purpose of Intake Manifold?

The intake manifold is positioned on top of the engine and it plays a vital role in the combustion process of your vehicle. 

It distributes the right proportion of fuel and air mixture meant for combustion to all the intake ports of the cylinder. The intake manifold distributes this air and fuel mixture evenly to the cylinders to help the vehicle to perform well.

Causes of Carbon Buildup in Intake Manifold

Carbon building up on the intake manifold can occur naturally because of how the engine functions or as a result of a malfunctioning component of your car’s engine.

It can be as a result of fuel and oil getting into some components of the intake manifold which later burns to carbon as they come in contact with high-pressure air during combustion.

The absence of airflow in the intake manifold will also cause carbon buildup. This usually occurs when the throttle body is dirty, causing it to become clogged, which is the reason airflow is restricted.

When Should I Clean My Intake Manifold?

If your car is showing a sign of stalling while it is warming up or when cool or has difficulty moving, one important component that needs to be checked and cleaned is the intake manifold. 

Carbon buildup on valves of the intake manifold will have a huge effect on your engine, thereby making your car show these symptoms.

Driving conditions also determine when you need to clean your intake manifold. If you drive in congested areas, you might need to remove carbon sludge from your intake manifold often.

Also, if you have used your car for up to 30,000-50,000 miles, it is advisable to clean your intake manifold because within this period carbon must have accumulated on the component.

how to remove carbon buildup in intake manifold

How to Remove Carbon Buildup in Intake Manifold

You can remove carbon buildup by using effective and special cleaners that will efficiently remove the carbon deposits from your engine. You need to follow a step-by-step process to get this done. 

Below are the steps to follow.

Step 1: Disconnect the air intake duct and battery cable

Before doing this, you have to ensure your engine is off, and then you can disconnect the air intake duct from the throttle body to ensure it is ready to work with the engine. 

You will also need to disconnect your negative battery cable to prevent electric shock during the process.

Step 2: Start cleaning the intake manifold

After wiping and re-attaching the intake duct, the next thing to do is to start cleaning the intake manifold. 

To do this, you’d need to pour the appropriate quantity of the cleaning agent you had chosen into the intake manifold then disconnect the vacuum line from your engine.

Step 3: Connect the intake hose to a bucket

You need to connect the intake tube into a bucket under your car to collect any fluid that will come out from the component during cleaning.

Step 4: Turn your engine on for a few minutes

When this is done, you will see the carbon deposits coming out in puffs of white smoke while your engine is still on. 

When this stops, pull your vacuum line out to stop drawing more fumes into the intake tube. You can repeat this process till you are satisfied all the carbon buildup is gone.

Step 5: Reattach the vacuum

To complete the process, you need to reattach the vacuum hose. After this, drive out your car to clear out any remaining liquid in the intake tube.

How do you clean an Intake Manifold without removing it?

The intake manifold can also be cleaned without removing it from your car and even without professional help. 

The first thing to do is to park your vehicle in an open space to avoid suffocation that could be caused by the exhaust fumes emanating from your engine.

The next thing is to get a power foaming cleaner, clean microfibre cloth, gloves, screwdrivers, and wrenches.

These are the basic equipment you will need for this process. The power foaming cleaner is specially made for the removal of grime, gum, and carbon deposits on the intake manifold.

The microfibre cloth is used to remove excess liquid from the engine while screwdrivers are used to disassemble hoses and tubes. This is followed by detaching the throttle and air intake duct.

You will need to separate the throttle valve from the air intake tube carefully. This does not require you to remove the throttle from your car but at this point, ensure your engine is off.

The next step is cleaning the throttle valve. You do this by spraying the power foaming cleaner on the throttle valve and mopping out the excess liquid using the microfibre cloth. After doing this, you attach the air intake tube back to the throttle valve.

Finally, wipe all dirt from the intake manifold. In doing this, you will need to disconnect the vacuum hose from the inlet manifold then spray the power foaming cleaner into the vacuum hose and allow it to settle for some minutes before connecting it back to the intake manifold. 

If these processes are completed successfully, your engine should begin to function optimally. 

Frequently Asked Questions

How can I tell if my carbon buildup needs to be cleaned?

You can determine when your carbon buildup needs to be cleaned if there is any visible carbon buildup in your intake manifold. However, without you noticing a visible carbon buildup, look out for common signs of carbon buildup in the intake manifold. Carbon buildup usually manifests itself in different ways. For instance, you can experience engine misfires, stalling, rough running, and poor acceleration. When you notice some of these signs, it is best to get rid of carbon buildup to avoid further inconveniences and damages.

Should you clean the intake manifold?

Yes! It is very important to clean the intake manifold especially if your engine has started displaying some faults. The intake manifold provides air to your engine to help it work efficiently. A dirty intake manifold will let harmful materials into your engine which can cause huge damages to it. Also, carbon buildup will clog the intake manifold and restrict air from flowing properly.

How do I know if my intake manifold is clogged?

When your engine begins to show symptoms of failure, there is a possibility that the fault is from a clogged intake manifold because when this happens, air will be hindered from flowing properly in the manifold and this will hinder the performance of the engine. Some symptoms that will manifest if your intake manifold is clogged include car stalling, engine misfires, engine overheats, and difficulty accelerating.

How do I clean the intake manifold?

You can use readily available items like vinegar or coca-cola with water to clean your intake manifold frequently. The vinegar or coca-cola will loosen up the sludge then you take it off with a scraper. However, if the carbon buildup on your intake manifold is very severe, it is advisable to take it to an automobile repair shop for professional services.

What will dissolve carbon buildup?

Household items like vinegar, coca-cola, kerosene, and mineral spirits can readily dissolve carbon. For a more effective result, other sophisticated solvents can be used to remove carbon from your intake manifold. They include but are not limited to acetone, ethyl acetate, dimethyl sulfoxide, ethanol, seafoam cleaner, degreaser, etc.

How often should I clean my intake manifold?

It is advisable to take your car to an automobile shop for professional cleaning at least once in two years. Changing engine oil frequently also helps reduce carbon buildup in the intake manifold. However, the intake manifold still gets dirty after you must have driven your car for a while. On this note, you might need to clean your intake manifold every 25,000 to 30,000 miles with a recommended cleaner.


It is helpful to be conversant with the basic steps on how to remove carbon buildup from intake manifold. This will help you ensure the smooth running of your vehicle.

Other times, you might still need to take your vehicle to a professional for proper inspection and servicing.

If you are concerned about the speed of your car and the longevity of your engine, it is important to keep carbon off it. As stated earlier, carbon buildup on your intake manifold will reduce the performance of your engine and if this is ignored, it will gradually shorten the lifespan of your engine.

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