Why Decarbonising Your Engine the Wrong Way Can Destroy It and How to Do It Right

When your car crosses 80,000–100,000 km, you’ve probably heard workshops recommending “engine decarbonisation” to restore lost power and efficiency.

But here’s the truth: most of these so-called de-carbon treatments are not just ineffective, some can even harm your engine.

At ICD Tuning, we believe in educating car owners about what actually works and what doesn’t. Let’s break it down and explain the right way to deal with carbon deposits, and why they form in the first place.

How Carbon Deposits Form

Every combustion engine burns a mixture of fuel and air. This process is never perfectly clean — tiny amounts of unburnt hydrocarbons, oil vapours, and soot stick to internal surfaces over time.

Here’s what contributes to this build-up:

PCV System

The Positive Crankcase Ventilation (PCV) system routes oily blow-by gases back into the intake manifold to be burned again, to reduce emissions. These oily vapours settle and mix with soot to create sticky deposits on intake valves, ports, and throttle bodies.

Low-RPM Driving Habits

Driving at low RPMs for prolonged periods (a habit many people have to “save fuel”) actually worsens the problem. Without higher exhaust heat and air velocity, the deposits don’t burn off and just keep accumulating.

Short Trips & Low Temperatures

If the engine never fully warms up or is stopped before reaching optimal temps, carbon builds up even faster.

At ICD Tuning, we see these patterns every day and help customers understand how simple habit changes can prevent unnecessary issues.

Why Not to “Decarbonise the Internals”

Many workshops offer chemical sprays, foams, or even pour-in treatments claiming to clean pistons, valves, and combustion chambers without disassembly.

Some also use hydrogen generator machines, which feed hydrogen gas into the intake so it burns along with fuel and supposedly “steam cleans” the combustion chamber.

Here’s why these methods are risky:

X The chemicals or hydrogen may loosen large chunks of carbon that then scratch cylinder walls or clog catalytic converters.

X In older, high-run engines, the carbon layer actually helps seal the gap between the piston rings and cylinder walls. Removing it aggressively (as hydrogen does) can increase clearance, reducing compression, increasing oil consumption, and accelerating wear, sometimes leading to the need for a full rebuild.

At ICD Tuning, we never recommend such risky procedures, and we explain why to every customer who asks. A Word on the Hydrogen Cleaning Business

Now, it’s important to note: we don’t blame the workshops or businesses that invested in hydrogen cleaning machines.

I understand that most of them were simply misled by aggressive and convincing marketing from equipment manufacturers.

The science behind these machines was poorly understood and the claims of “miracle cleaning” sounded good on paper. Many workshops genuinely believed they were offering their customers a valuable service and spent significant money buying these machines, hoping to help.

We sympathise with these businesses because they too fell victim to misinformation and were trying to keep up with trends in the industry.

That’s why we always recommend workshops and car owners alike to first understand the engineering and the consequences before investing in such solutions. Knowledge is power, and it can save both money and engines.

How Hydrogen Cleaning Works and Why It’s Not Always Good

Hydrogen generators produce a mix of hydrogen and oxygen gases (sometimes called HHO), which is fed into the intake while the engine runs.

When hydrogen enters the combustion chamber:

• It burns much faster and hotter than petrol/diesel.

• The high heat and reactive water vapour it creates can burn off carbon on pistons, valves, and chambers.

Sounds good, but here’s the problem:

• In engines with heavy deposits, this can strip away the carbon “layer” that was sealing worn surfaces, exposing scratches and increasing blow-by.

• This loss of sealing reduces compression, causes higher oil consumption, and increases wear because the cylinder walls are left bare and exposed to more friction.

• In some cases, it can even damage or crack already weak components if not controlled properly.

That’s why at ICD Tuning, we advise against using hydrogen cleaning, especially on high-mileage engines.

The Right Way to Decarbonise

If your engine has significant carbon deposits, the correct way is to manually access the affected areas and clean them properly.

At ICD Tuning, this is exactly what we recommend and perform for our customers:

Intake Manifold & Ports

Remove the intake manifold and physically clean the ports and valves using walnut blasting, dry ice blasting, brushes, or approved solvents.

Throttle Body

Clean the throttle plate and housing.

PCV System Check

Inspect and replace faulty PCV valves that may be letting excessive oil vapour through.

Driving Habits

Occasionally revving higher and driving at highway speeds (once the engine is warm) can help burn off minor build-up over time.

Tips to Prevent Carbon Build-Up

• Warm up the car properly before driving hard.

• Avoid driving at very low RPMs all the time and don’t “lug” the engine.

• Use good quality fuel and oils.

• Periodically clean or replace PCV valves.

• If possible, occasionally take the car for a longer, spirited drive to clear minor deposits.

We routinely guide our customers at ICD Tuning on these preventive steps, because prevention is always better than cure.

Summary

Carbon build-up is a natural consequence of internal combustion, especially in modern engines with PCV and direct injection.

Instead of relying on gimmicky sprays, chemicals, or risky hydrogen cleaning of the internals, have a professional clean the intake system manually, and maintain healthy driving habits.

At ICD Tuning, we take pride in educating customers and offering only safe, effective decarbonisation methods.

Removing carbon from the wrong places can actually harm your engine, increasing oil consumption, lowering compression, and accelerating wear, often requiring an expensive rebuild.

Take care of your engine the right way, and it will take care of you.