Come to think of it; internal combustion engines are a violent invention. They are all about controlled explosions in a tight enclosure. Burning gasoline produces explosive energy, heat, carbon, and other waste gases.
While most of the carbon powder burns and the rest exits with the exhaust gases, some remains stuck onto the piston heads, rings, valves, and cylinder walls.
Over time, the carbon buildup becomes too much to the extent of causing issues in the engine. It will block valves, wear out the rings faster, increase fuel consumption by making the engine less efficient and generally lower your engine’s lifespan.
What Are Piston Rings? What Do they Do?
Naturally, your pistons aren’t a snug fit to your cylinder walls. If they were, they wouldn’t move as efficiently as they do. To span the gap, designers use more pliable rings to create a tight seal between the piston and the cylinder walls.
The rings sit in grooves around the cylinder head.
Piston rings prevent pressurized air and fuel mix from escaping the cylinder and leaking into the oil sumps. They also prevent excessive oil from entering the combustion chamber and burning up.
Most engines have three piston rings.
- A top and second ring. They create a tight seal between cylinder walls and the piston head to keep oil out and combustion gases in
- An oil ring at the very bottom to clean oil off the cylinder wall and back into the oil sump as the piston retracts. This leaves a very thin oil film to lubricate the rest of the piston head and rings.
Over time, piston rings gather gunk and carbon from all that oil, air-fuel mix, and exhaust gases they interact with.
Cleaning the residue could prolong its life by removing the residue before it wears down the piston rings or gum them up. Gummed-up piston rings will not push out against the cylinder walls as new clean rings would.
This will lead to low compression, burning oil, escaping combustion gases, and a considerable loss in engine power.
What to Do When Your Piston Rings are Dirty and Stuck
Ideally, piston rings should last an engine’s lifespan. If they don’t, the perfect way to fix them is opening up the engine and replace them.
Cleaning Piston Rings Without Removing Them
Needless to say, this is much work. You will pay hours in labor – unless you can do it yourself. People are keen on cleaning their piston rings without removing them.
The problem is that carbon is very inert. Very few chemicals can dissolve carbon without corroding your engine. Therefore, any product you use will never attain 100% cleanliness. It might dislodge some bits and prevent further buildup, but don’t expect magical results.
Try Fuel Injector Cleaner and Combustion Chamber Cleaners
In theory, fuel system cleaners like Techron Concentrate from Chevron could extend their cleaning effect to the piston rings. They are easy to use since they go into the fuel tank, mix with your fuel and enter the combustion chamber through the injectors.
Even though the majority will combust before getting to the piston rings, you might get a little cleaning effect on the piston rings.
Try Detergent and Dispersant Oil Additives
Oil additives have the best chance of getting to the piston rings since the piston interacts with oil before the combustion cycle.
Any engine cleaning additive that contains detergents and dispersants could help dislodge some carbon from the piston rings letting it fall back to the sump.
However, since the middle and top rings only interact with a tiny film of oil, the cleaning effect will again be very limited.
ProTip: Since they are relatively cheaper than overhauling your engine, using high-quality engine flush and fuel additives like Amsoil Engine and Transmission flush is still a good idea
You can try out any other carbon residue cleaner. These could be products you spray onto the throttle body with the engine running or something you put in the intake manifold before starting the car.
It is no guarantee it will cleanse your piston rings, but you could get rid of some of the carbon residue on other parts of the engine while at it.
Cleaning Piston Rings in Place is Hard: Prevention is Better
With so little cleaner getting to your piston rings, regardless of what non-removal method you choose, prevention remains the only viable option to prolong your piston ring’s lifespan.
Here are some basic rules you should live by to keep your engine as clean as possible
Use High-Quality Fuel With Cleaning and Optimization Agents
The most efficient thing you can do is fuel at top-quality stations with improved oil. Any oils with additives that clean the engine or improve fuel atomization will do the trick.
The detergents will clean soot and carbon before it sticks. Atomization-improving formulas will make your fuel injectors more efficient hence reducing how much soot and carbon your engine produces during the combustion cycle.
Finally, high-quality fuel has fewer impurities—the fewer the impurities, the less residue you will have at the end of each combustion cycle.
Service Your Engine Regularly
Your piston rings play a major role in keeping your piston head lubricated without leaking tons of oil into the combustion chamber.
This puts them in constant contact with your engine oil. Giving them the cleanest oil possible makes their work easier.
Even though most manufacturers give mind-blowing 10k or 15k mile service intervals, servicing your engine every 5K or twice a year is a unanimous standard among mechanics and car enthusiasts.
It might cost you more in oil, but it will save you tons in dirty oil-related issues. Preventable damage happens if you don’t change your engine oil.
Use High-Quality Oil of the Correct Viscosity
Apart from changing your oil regularly, you should also ensure that you use high-quality synthetic oil of the highest recommended viscosity.
Synthetic oil is more consistent and retains its properties better than natural blend oils. This reduces its chances of gumming up your engine (piston rings included) more.
Using the heaviest recommended oil for ambient temperatures will also give you the thickest oil that properly closes the gap between the cylinder walls and the piston rings. This leaves less oil leaking into your engine.
ProTip: We have done a couple of articles on choosing oil grade. Here are a few:
Can I switch back to regular oil after synthetic oil?
What happens if you go too long without an oil change?
Oil produces more carbon when it burns than the air-fuel mixture. Minimizing how much your engine burns will have a profound impact on how much carbon and soot residue you make.
Signs and Symptoms of Dirty or Ruined Piston Rings
If your piston rings break down or stick, your engine loses compression. It will leak combustion gases into the oil, and oil will also leak into the combustion chamber. Such unwanted occurrences profoundly impact the engine, and the symptoms are hard to miss.
Your Engine Will Feel Lethargic
Leaking combustion gases during the power stroke robs your engine of all that juicy explosion it needs to make torque and horsepower.
The impact of the loss varies depending on how bad the leakage is or how many pistons are leaking.
It could range from reduced acceleration performance to profound power losses that leave your car stalling when idle with the AC on.
Your Car Will Smoke More (Blue Smoke)
Blue smoke is a sign of burning oil. If the piston rings break down or get stuck, they will let more than usual oil leak into the engine. This oil will burn up, giving the characteristic blue smell and burning oil stench.
Your Oil Levels Will Drop Fast Without Visible Oil Leaks
Even though it is normal for your engine to burn some oil, It shouldn’t burn a lot to warrant frequent oil top-ups long before it is due for an oil change.
If you find yourself having to fill up a couple of quartz before your next oil change and you can’t see any oil smears around your engine or an oil puddle under the engine, chances are you are burning that oil.
A couple of things could make your engine burn oil. Worn out or stuck piston rings is one of those things.
Test for Compression
Without the perfect piston ring seal, your engine will have less compression on affected cylinders. Using a compression testing kit and the correct testing procedure can help you figure this out. Low compression could also mean other things, like the valves being stuck open.
What Can I Use to Clean My Piston Rings?
You can use any carbon residue cleaner or dedicated engine flush compounds to decarbonize your piston rings to some extent. This ranges from:
- Fuel additives to clean the engine
- Fuel injector cleaners
- Air intake system cleaners
- Oil additives to clean you engine
- Fuel formulas with cleaning additives or detergents
Follow the manufacturer’s directions on use to get the maximum benefits from the cleaner.
Does Fuel Injector Cleaner Clean Piston rings
Theoretically yes. Fuel injector cleaner can dislodge the sludge on your piston rings – if it gets to them before burning in the combustion chamber.
However, since fuel injectors only spray fuel just before the combustion cycle, chances are very minimal amounts of the cleaner will make it to your piston rings before it burns up.
This is the main issue why any fuel-side injected carbon cleaners might not have a profound impact on dirty piston rings.
How to Clean Piston Ring Grooves
Piston ring grooves are the cutouts where piston rings sit. The only way to access them is by removing pistons from the engine, removing the piston rings (or what remains of them), and using something soft to clean the groove manually. You can use some gasoline as a liquid to aid the cleaning.
How Do You Unstick Piston Rings Without Removing the Engine?
If you know your piston rings are leaking but can’t afford or bother to fix them, you could try a temporary fix by pouring some brake fluid into the combustion chamber through the spark plug holes.
Let about 1/4 of your cylinder’s volume worth of brake fluid sit in each cylinder overnight. You will have to siphon most of it before reassembling and running your engine.
How Do You Temporary Fix Worn Piston Rings
A temporary fix would be using thicker oil. This will help your rings form a better seal between the piston and the cylinder walls reducing how much oil you burn and how much compression your engine loses.
Does WD 40 Remove Carbon?
While WD 40 can clean some carbon buildup, it has substances that could harm other parts of your engine. It won’t be that forgiving on seals and gaskets in your engine.
Bottom Line
While you could try to clean piston rings without removing them, this is only practical if your piston rings haven’t started gumming up yet.
As a preventative measure, you can dislodge the few carbon residues already on the engine before it becomes a problem. This, combined with using the correct fuel and oil, will help keep your cylinder walls, pistons, piston rings, valves, and injectors clean for longer.