Top End Cleaners – How to Pick the Best One

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Before and After Top End Cleaning

Have you ever taken your car in for a simple oil change and the shop recommends you have a “top end” cleaning service (sometimes called induction cleaning) done to it? 

You may wonder if that was just a bunch of upsell B.S. or if it is actually a legitimate service that your car needs. I mean, who really knows with some shops, right?

The real answer is that if you drive a modern car with direct injection, you can pretty much guarantee that you will need to have this service done. In most models, you’ll want a top end clean about every 25-50k. The reason for the frequency of this service is that direct injection cars are not able (in most cases) to wash away the carbon that builds up on the valves and pistons on their own.

What is top end cleaner? 

These special cocktails of caustic cleaning chemicals cut through all the built up carbon on your valves and pistons to return your engine to a smooth running condition.

Why do you need a top end cleaner?

This is just how it is with gasoline direct injection vs port injection (and high compression engines). The simplified reason is that with the design of these newer engines, the gasoline no longer gets injected where it can wash over the valves, and in some cases the compression is so high from the factory it doesn’t take much of a carbon layer on the pistons to throw everything off. 

A Carbon-Covered Piston on a Honda J-Series Engine

With direct injection, the gas gets injected directly into the cylinders, much like a diesel. This engine design is much, much better for performance and fuel economy. Well, at least until your valves get coated in nasty carbon and your pistons have enough of a carbon layer to foul the air/fuel ratios.

When your valves and tops of your pistons are caked with carbon, this can cause high compression issues like detonation pinging, this is because the engine computer can no longer compensate enough for the added compression. Another reason why it is imperative to run high octane gasoline in newer cars, or an octane booster additive. This helps prevent the engine from pinging itself to death. 

How to decarbonize your engine with a top end cleaner. 

When carbon gets bad enough to mess with the performance of your car, the best way to fix it is with a decarbonization procedure. There are many options available, some even from the auto manufacturers themselves. It can be difficult to choose which one to buy, which is why we came up with an easy guide of what are (in our experience) the best top end cleaner options to super clean your engine. 

To make it easier to choose, we’ll break the types of cleaners into two main categories, regular maintenance and heavy-duty cleaners. 

Best top end cleaners for regular maintenance:

In this category are the regular maintenance fuel system cleaners, which can prevent some of the issues that lead to the need for a severe top end cleaning procedure, nipping the problems in the bud before they can happen.

Generally these are much easier to use than the heavy-duty repair top end cleaning procedures. In fact, for all of the cleaners in this category, you can just dump them right into your fuel tank and they will work alongside the gasoline to make sure that your injectors and combustion chambers stay in tip top shape.

Chevron Techron Fuel System Cleaner

Techron is unique in that Chevron actually adds this fuel system additive to their fueling station tanks directly. It has long been regarded as quite the magical additive that makes fuel mileage go through the roof. Pretty good bonus if you happen to use a Chevron station regularly!

Fortunately, for those of us that don’t see many Chevron stations around, Chevron sells this excellent fuel system cleaner as a concentrate that you can add directly to your fuel tank yourself.

Usage Interval Information:

Chevron suggests than their Techron complete fuel system cleaner concentrate is best used at every 3,000 mile interval. Most people will be just fine with using it once every oil change which may be closer to 5k or 7500 miles with the extended oil change intervals nowadays.

The recommended use is to dump the measured amount directly into your fuel tank. This varies depending on the size of your particular vehicle’s tank size, but you can use the measuring information below to determine the right amount.

Dosing Information for Techron Concentrate

Chevron recommends that you use 1oz of Techron Concentrate additive for every 1 gallon of gasoline.

Chevron Techron Ingredients:

Techron fuel system cleaner concentrate has five main ingredients:

  • Distillates, hydrotreated light
  • Solvent Naptha (petroleum), light aromatic
  • Stoddard Solvent
  • 1,2,4-trimethlybenzene
  • PEA (detergent), Polyether Amines

BG 44k Fuel System Cleaner

BG Product’s 44k fuel system cleaner is the #1 fuel system cleaner (according to BG.) While I’m not entirely sure how they base their claims, the point still stands that it IS a very popular and effective fuel system cleaner. They also claim that mechanics and drivers choose 44k in a 4 to 1 ratio versus other cleaners.

BG’s claims aside, in our own experience we have seen increased performance and mpg when using it in our test cars. This tracks with the claims that BG makes as to what 44K is designed to do.

BG says that 44k can:

  • Restore your engine’s performance
  • Restore and improve fuel efficiency
  • Increase your engine’s power output
  • Reduce exhaust emissions down to factory levels

Dosage information for BG 44K

BG recommends one full can of 44k per full tank of gasoline.

Ingredients of BG 44k Fuel System Cleaner

If you’re wondering how exactly that BG 44k pulls off this type of engine magic, you can see the actual ingredients listed below:

  • 1,2,4-trimethyl benzene, 0.5-1.5%
  • 10-30% Stoddard Solvent
  • Solvent Naptha (petroleum), light aroma, 1-5%
  • Ethylbenzene, 0.1-1% 
  • Naptha (petroleum), hydrotreated heavy, 15-40%

Sea Foam Motor Treatment

I did have a hard time picking a category to put Sea Foam in, as it is a incredibly versatile product that can be used for many different applications in a bunch of different ways. I ended up adding it to both categories, as they have products that do both regular and heavy-duty induction cleaning very well.

Seafoam motor treatment was the first experience I had with fuel system cleaners, and to this day remains one of the most popular additives for engine cleaning.

Seafoam Dosage Information

  • When adding to your tank at every oil change, use 1oz. of Seafoam for every 1 gallon of fuel.
  • For heavy duty cleaning, use 2oz or more per gallon of gasoline.

Seafoam Motor Treatment Ingredients

  •  40-60% Pale Oil (CAS 64742-54-7)
  • 25-35% Naphtha
  • 10-20% Isopropyl Alcohol (IPA)

Powerful top end cleaners for heavily carboned engines:

Theses types of cleaners are meant for a more heavy-duty cleaning, and are usually not used as often as the other types with a set interval.

Examples of use for these top end cleaners would be in an engine that has seen severe duty, or one that has had a lack of maintenance.

AcDelco Top Engine Cleaner – Part# 10-3015, 19355198

Also well known as GM top end cleaner, this is tough stuff. Many people use this one as a complete top end restore for an engine that has been neglected for a long time. When using it, you’ll want to be absolutely sure that you wear gloves and goggles. It’s potent stuff and an accidental splash in the eye is not something you’d want to experience.

The ingredients of GM top end cleaner are:
  1. 2-Butoxyethanol (an ethanol mixture that has had one of the methyl hydrogens is replaced by one from the butoxy family)
  2. Naptha (pretty close to kerosene, distilled petroleum in most cases)
  3. Methyl Isobutyl Carbinol (an acetone derivative that mixes well with additives)
  4. 9-octadecendic acid (pharmaceutical solvent)

Mopar Combustion Chamber Cleaner – Part# 4318001AD

This may be the most popular top end cleaning product that I have ever come across in the heavy-duty cleaning category. Don’t let the brand name fool you into thinking this is only good for Mopar vehicles. In our testing we have used this cleaner (sometimes abbreviated to MCCC) in many different makes and models, all with excellent results.

The ingredients list for MCCC are:
  1. Mineral Spirits
  2. Isopropyl Alcohol
  3. Naptha (pretty close to kerosene, distilled petroleum in most cases)
  4. Ethyl Benzene

How to use top end cleaners

Top end cleaners are mostly designed to be sucked right into the intake manifold through a vacuum port. This does require following directions carefully, as it can result in engine damage if done incorrectly. 

The biggest thing to worry about is feeding the engine too much of the cleaner at once. For that reason, it is recommended that you use a vacuum line or port about ¼ in diameter. This will act as a basic metering device. 

  • Step 1 – Warm the engine up to normal operating temp before doing anything.

This is an important step, because the warmer the engine internals are, the better the cleaner will be able to soak into the carbon build up.

  • Step 2– Add the top end cleaner

Each of the cleaners is a little bit different as far as dosing goes, but the general idea is to suck in the required amount through the intake manifold vacuum port (with the engine running and warmed up) and then immediately shut the engine off. 

  • Step 3 – Let the engine sit turned off with the cleaner in it for about two hours, to allow the solvents to soak into the carbon. 
  • Step 4 – The Smoky Drive – Burning all the carbon out

After the rest period, you’ll want to warm the car up to normal operating temperature. Do not rev the car above 2000 rpm until it is fully warmed up.

After the engine is at normal operating temp, start to drive the car as you would normally, taking it a bit easy at first until you are SURE that all of the cleaner has been burned out. You will see huge James Bond style smoke screens coming out of your exhaust for the first 10-20 minutes, this is normal.

Hop onto the highway and do a slow pull from 60 up to 80 mph and see if the car behaves normally, or if it wants to misfire. If it drives normally, continue to do slow pulls until you see the smoke start to fade.

If the misfires don’t go away, back off and slow the car down. Drive some more at low speeds to get more of the cleaner burnt out of the engine before taking it back onto the highway.

Once you are sure that ALL of the misfiring and smoke is completely gone, then take the car for the old “Italian Tune-up” also known as a WOT (wide open throttle) run. This will help to clear out any leftover carbon and junk.


If you have a neglected engine that needs the heavy cleaning power of a drastic top end cleaner, you’ll want to make sure that you DEFINITELY change the oil after performing the decarbonization process.

The solvents in the cleaner have the potential to make your oil basically worthless for lubrication, plus you’ll want to empty out all the contaminants that made their way down into the oil, trust me on that.  



2 thoughts on “Top End Cleaners – How to Pick the Best One”

    1. Hi Bob,

      The indicators would be a slight misfire or rough running, especially at idle. Engines with carboned valves tend to smooth out as the revs increase, but at idle it is more noticeable.

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