Pistons are the mechanical marvel of the 20th century. Without them, the internal combustion engine would not exist. However, there’s more to pistons than meets the eye. Several smaller components are necessary for the pistons to function the way they do.
Piston rings are one of those parts. They play a vital role in sealing the combustion chamber and lubricating the cylinder walls.
For various reasons, piston rings can go bad. When they do, they can compromise the performance of your engine to a point where it no longer operates efficiently. We have put together a guide that will tell you pretty much everything you need to know about piston rings. Here, you’ll find symptoms, fixes, causes, and other important information.
What are Piston Rings
The combustion process is how gasoline engines make power. By combining air and fuel and lighting it with a spark, combustion creates a controlled explosion that forces the piston down and ultimately rotates the crankshaft. To force the piston back up, you need a sealed combustion chamber.
Piston rings create a seal between the piston head and the wall of the cylinder wall. They allow for an oil layer to prevent metal-on-metal contact. When you add angles to the mix, the piston heads need structural support, which the rings provide. Piston rings also conduct heat, moving it away from the piston to the engine block. Overall, these tiny rings are an essential part of how your engine works.
How Piston Rings Work
All engines use a three-piston-ring configuration — a top compression ring, an intermediate compression ring, and an oil control ring.
The top ring provides a final seal for all combustion gases. The intermediate ring aids sealing and oil layering, while the bottom ring controls the amount of oil lining the cylinder wall.
The intermediate ring is also called a wiper ring. Its curved surface scrapes excess oil from the wall, preventing it from entering the combustion chamber. The oil ring returns this excess oil to the oil pan by allowing it to flow through small indents on the ring surface.
Why Piston Rings Fail
Like many engine components, piston rings experience heat expansion. Car engineers factor this in, along with the structural changes that rings might experience.
This is one reason why engines have a “breaking-in” period. It’s the main reason that incorrectly breaking in your engine can cause premature oil burn issues and high oil consumption.
Although this can cause your piston rings to function incorrectly, they will not fail if you don’t break in your engine correctly. Friction is the primary killer of piston rings. If the piston rings start rubbing against the cylinder wall, it is game over.
What Causes Piston Ring Failure?
Piston rings are engineered to withstand high temperatures and low lubrication situations beyond normal operation. However, even under normal conditions, they can fail. When that happens, it often implies a total engine rebuild. Here are some of the common causes:
- Engine overheating
- Oil dilution
- Rich air-fuel mixture
- Age
Engine Overheating
If your engine overheats, it can cause catastrophic damage to internal and external components. The piston rings are some of the first parts to suffer when that happens.
The top compression ring breaks into pieces as the heat moves down from the piston crown. The other two rings will probably seize or have serious signs of damage as well.
Oil Dilution
Many modern vehicles experience a phenomenon called blow-by. This is when fuel vapors are forced past the pistons into the crankcase. The air-fuel mixture ends up in the crankcase and where it mixes with the oil.
Diluted oil can reduce the lubrication properties of oil and cause metal-on-metal contact between the rings and cylinder walls. This can cause your pistons to fail.
Rich Air-Fuel Mixture
A rich air-fuel mixture can cause abrasive soot particles to accumulate in the oil. So many vehicle issues cause a rich-fuel mixture and it is often shrugged off as a non-issue. In most cases, this engine condition causes long-term damage.
Age
Any component in your vehicle is subject to wear and tear. The constant heating and cooling of the pistons and the abrasive nature of the up-down piston movement wear out your piston rings.
Of course, regular maintenance usually means that other engine components will fail long before your piston rings do.
What are the Common Symptoms of Piston Ring Failure?
The symptoms of piston ring failure are very visible. They almost exclusively point to this part being the source of your issue. Here are the most common symptoms:
- Excess oil consumption
- Blue exhaust smoke
- Reduced performance
Excess Oil Consumption
As the piston rings wear, oil enters the combustion chamber and burns up. Of course, this oil doesn’t return to the oil pan. You may find that your oil levels are lower than normal if you have an issue with your piston rings.
Blue Exhaust Smoke
Exhaust smoke that has a bluish-gray tint to it points to oil burning up in the combustion chamber. Worn piston rings are a common cause of this type of smoke.
Reduced Performance
Your engine needs 3 things to run properly — fuel, spark, and compression. Remove any of these three and you’ll notice a drop in performance. Piston ring failure often reduces the amount of compression in the cylinder, sometimes to a point where there is virtually no compression at all.
How to Prevent Piston Ring Failure
You can avoid piston ring failure. A couple of preventative measures will ensure that your piston rings will be the last component to fail in your vehicle.
Regular Maintenance
Regular oil changes can prevent abrasive material from wearing out your piston rings. Dealership oil change intervals are longer than what is generally recommended. Change your oil frequently, approximately every 4,000 to 6,000 miles and your engine will last a lot longer. Additionally, fixing issues that cause poor engine running conditions will also extend the life of your piston rings.
Changing your air filter or cleaning a reusable one regularly can prevent abrasive particles from entering the combustion chamber.
Oil Catch Can
Oil catch cans are a common feature on modern turbocharged vehicles. They filter the blow-by gas that re-enters the engine through the PCV system, separating oil from other components like carbon and gasoline. This can prevent your oil from being diluted.
Even if your vehicle already uses an oil catch can, it is recommended that you swap it out for a higher-quality, baffled one. This slight change can make a massive difference to the longer-term health of your piston rings.
Don’t Push Your Engine While It’s Cold
This is probably the most underrated way of extending the life of your piston rings. Most piston ring damage occurs during brief trips before the engine reaches operating temperature. If you can’t take the time to let your vehicle warm up, avoid excessive acceleration after a cold start.
How to Fix Failed Piston Rings
Aside from replacing your piston rings, the only other option you have is to use a piston ring sealer. Add this compound to your engine oil to add more viscosity, and hope that it creates a film around the piston rings, sealing up the combustion chamber.
Although this can work if your piston rings are worn due to age, it will do nothing if they are seriously damaged. You can also achieve this same effect by just switching to an oil with a higher weight. Check out our selection of engine oils for a good option. It is also not a permanent fix, as major piston ring wear is usually caused by other engine problems.
Can I Replace Failed Piston Rings?
The short answer is yes. It does require a full engine rebuild, but it can be done. You’ll need quality piston rings, which we can provide, time, and knowledge However, even if you can replace your piston rings, it may not return your engine to full health. Simply because the new rings are unlikely to fit perfectly in the groove as the original ones did.
Can I Drive with Failed Piston Rings?
In most cases, piston rings fail progressively rather than catastrophically. You can often drive with a failed piston ring, given that the issue is localized to a single cylinder. However, depending on the extent of the damage, you might experience a whole slew of problems including misfires.
Get Good Oil, Save Your Piston Rings
In an ideal world, your piston rings would last forever with regular maintenance and elbow grease. Even though you know that eventually, you will have to part with your vehicle as it ages, that doesn’t mean that you will not do everything in your power to keep it in good condition.
Here at eEuroparts.com, we know this. That is why we offer a full list of tailored parts for a wide range of vehicles. All you need to do is pick your vehicle from the dropdown list and the parts that you need.
