Northern VA Auto Repair


Carbon Junk

Q: What is Carbon Buildup?

Carbon buildup is mostly a problem with today’s newer “direct injection” vehicles.

Think of your engine like a fireplace. When a fireplace burns fuel, it releases fumes – waste byproducts of smoke and carbon. In a fireplace these fumes go out the flu and deposit along its walls on the way out. The more fuel you burn, the more caked on the deposits become, eventually blocking off the airflow of the flu and impacting the fireplace’s ability to warm the house.

It’s similar in a car. When auto fuel burns, it releases the same kind of waste byproducts as a fireplace depositing them on the intake manifold, throttle body, and cylinder head valves.

The problem is that this carbon buildup restricts airflow to the engine and causes obvious, and sometimes significant, problems.

What are the Symptoms of Carbon Buildup?

· Engine vibration or shaking

· Jerking or surging at stops

· Illuminated Check Engine Light

· Cold start misfires

How to Remove Carbon Buildup

When you have these types of engine issues, take your vehicle to a reputable Auto Technician, and have them check it out. If they discover that you have carbon buildup affecting your engine, most of the time the Auto Technician will need to remove the intake manifold and manually clean out the carbon.

There are other (less effective) ways to remove carbon buildup. For example, some shops use “walnut blasting,” spraying the manifold with crushed walnut shells to, in essence, scrape out the carbon. However, walnut blasting may not get all of the carbon out of the engine, and errant walnut shells could get into the engine causing friction (and damage) where you don’t want it.

The best way to get rid of carbon buildup is to remove the intake manifold and manually remove it with the use of chemicals and tools.

How to Prevent Carbon Buildup

· Get regular oil changes, and use the correct fuel for your vehicle. Using top-tier fuel can help but will not totally prevent buildup.

· Put the pedal to the floor, and “blow the junk out.”

If you are mostly driving commuter miles, take your car out on the freeway and let it go. (Not only could this be a lot of fun, but it will help remove excess buildup!)

· A word about fuel additives:

While many fuel additives claim to prevent carbon buildup, it’s our experience that not all of them really do.

The fact is that carbon buildup is a byproduct of a direct injection engine, and cleaning it out needs to be part of your regular vehicle maintenance.


Auto Care