Carbon Cleaning Comparsion

Different Methods of Inlet Valve Cleaning

There are several methods available for cleaning carbon buildup on intake valves, each utilizing different techniques and technologies. While walnut blasting is widely recognized as one of the most effective solutions, other methods are also used in the industry. These include:

Cleaning Methods:

  1. 1️⃣ Blasting
    • Walnut Blasting - Probably the most cost effctive and safest way to remove the carbon buildup without disassembly
    • Synthetic Blasting (aka Tunap microflex) – A non-walnut alternative that uses specially formulated synthetic media to remove carbon buildup without disassembly.
  2. 2️⃣ Chemicals
    • Solvents
      • Direct Injection Valve Cleaner
      • Wynn's Air Intake Cleaner 1L MultiServe
      • Tec4 Air Intake & EGR Cleaner
      • Liqui Moly Pro-Line Throttle Valve Cleaner
      • CRC GDI IVD® Intake Valve & Turbo Cleaner
      • Sea Foam Spray – Intake Valve Cleaner
      • Berryman® Intake Valve & Combustion Chamber Cleaner
    • Additives
      • Liqui Moly Valve Clean
      • Valvoline™ Fuel Injector + Intake Valve Cleaner
      • BG 44K Fuel System Cleaner
      • Red Line Complete SI-1 Fuel System Cleaner
      • Chevron Techron Concentrate Plus Fuel System Cleaner
    • Foams
      • Pro-Tec Carbon X Combustion Chamber Cleaner K1+K2
      • Gumout® Foaming Intake Valve & Turbo Cleaner with CarbonClear™
  3. 3️⃣ Hydrogen
    • A process that injects hydrogen gas into the intake system to help break down carbon deposits through combustion.
  4. 4️⃣ Cryogenic Cleaning
    • (CO₂ Blasting) – Uses dry ice (solid CO₂) pellets to freeze and dislodge carbon buildup. The pellets evaporate upon impact, leaving no residue behind. More commonly used in industrial and aerospace applications but has been tested for automotive carbon cleaning.
  5. 5️⃣ Ultrasonic Cleaning
    • Some shops remove intake components and use ultrasonic vibration baths to dislodge carbon deposits. This method is labor-intensive and not practical for on-vehicle cleaning.
Walnut Blasting Example

Walnut blasting is a non-abrasive and natural engine cleaning method that has become increasingly popular in recent years. It involves blasting finely ground walnut shells at high pressure against engine components to remove carbon buildup and other deposits that can impact engine performance.

Hydrogen Cleaning Example

In our tests hydrogen cleaning did nothing to clean the inlet valves

Comparison of Intake Valve Cleaning Methods

Process Name Outcome Safety Cost Description
Walnut Blasting ★★★★★ ★★★★★ ★★★☆☆ Uses walnut shell media to safely remove carbon deposits without damage.
In our opinion the very best procedure for carbon cleaning of inlet valves. Couple with Ultrasonic cleaning of the inlet manifold/egr and you will effectively remove all the cabron.
Synthetic Blasting (Tunap) ★★★★☆ ★★★★☆ ★★★☆☆ Synthetic particles used instead of walnut shells, effective but less aggressive.
Unlike Walnut blasting a seperate chemical is used to break up the synthenic shells and carbon after the first chemical has blasted the carbon. I think using a vacumn and removing the carbon is still a better apporach.
Solvents ★★★☆☆ ★★☆☆☆ ★★★★★ Chemical solvents dissolve carbon deposits but may not reach all areas.
Whilst I am sure they will remove some carbon, I have tested them and found LOTS of carbon remains
Solvent Machines ★★★☆☆ ★★☆☆☆ ★★★★★ Like a Basic Solvent approach but typically the garage has been sold a fancy machine to make them "think" its better than simply spraying in a solvent.
I suspect this kind of machine is bought by garage simpletons.
Bottom line is: It uses a chemical and air line and a regulator. It doesn't need to be in a big box with buttons on it, it is markerting BS
Foams ★★★☆☆ ★★★☆☆ ★★★★☆ Expanding foam cleaners target intake deposits but require frequent applications.
Whilst I am sure they will remove some carbon, I have tested them and found LOTS of carbon remains
Fuel Additives ★★☆☆☆ ★★★★☆ ★★★★★ Fuel-based cleaners claim to reduce carbon, but less effective for direct injection engines.
But how can these clean inlet valves on DI engines when no fuel is sprayed on them? I don't think they work as a result
Hydrogen Cleaning ☆☆☆☆☆ ★★★☆☆ ★★★☆☆ Injects hydrogen gas to burn off carbon, but effectiveness is debated.
We have tested this method and found zero difference in the carbon before and after. I simply don't see how the hydrogen can remove the carbon from the inlet track. I understand it might remove carbon inside the cylinder but that don't help DI engines
Cryogenic Cleaning (CO₂ Blasting) ★★★★★ ★★★☆☆ ★★★☆☆ CO₂ pellets freeze and dislodge carbon; clean and residue-free but costly.
Will clean the valves as well as Walnut Blasting, but where does the carbon go, it isn't removed like with walnut blasting, so slightly more risky in our opinion
Ultrasonic Cleaning ★★★★★ ★★★☆☆ ★☆☆☆☆ Uses ultrasonic waves to loosen deposits; requires part removal. Major draw back is you've got to remove the cylinder head to do it
This is the best method to clean things like Intake Manifolds, Cylinder Heads, EGR valves etc as these parts are removed to perform walnut blasting
Manual Scrubbing ★★☆☆☆ ★☆☆☆☆ ★★☆☆☆ Manual labor using brushes or picks
Extremely labor-intensive and risky as you could damage something, i.e. damage a valve or valve seat, get something lodged in etc. Sometimes done with the aid of a chemical. Issues arrise with removing the carbon and chemicals also.
Quite often people use Mr Muscle Oven Cleaner to clean the carbon off the valves. This is a very bad idea as it can damage the valves and valve seats.