Signs of Bad Piston Rings

Most of the engines in today’s cars have a specific number of cylinders. The most common engine types have four-cylinders or six-cylinders, but there are many eight-cylinder engines on the road as well. At the high end of the auto market, there are luxury cars and exotic sports cars with ten-cylinder, twelve-cylinder, and even sixteen-cylinder engines.

For each cylinder that is found in a particular car’s engine, there is a piston located within it. The piston is a cylindrical piece of metal that moves up and down inside each cylinder, compressing the air-fuel mixture and capturing the force created by the combustion process. This force is then transferred to the crankshaft, via the connecting rod. The power that is produced by all of the engine’s pistons, firing in a preset sequence, is transferred to the car’s transmission and then to the wheels, propelling the car down the road.

Located between each piston and the wall of its cylinder, there are three spring-loaded metal rings. Each ring is inset into its own groove, which goes completely around the circumference of the piston. These are your piston rings.

Piston rings have multiple functions, which include:

1. Sealing the piston in the cylinder, to prevent combustion gases from escaping from the cylinder into the crankcase, which would reduce the engine’s power output.
2. Managing the distribution of oil between the cylinder wall and the piston, providing enough for proper lubrication, but keeping it out of the combustion chamber.
3. Transferring the intense heat of combustion from the piston to the cylinder wall, where it can be dissipated through the actions of the engine’s cooling system. 4.Keeping the piston from banging against the cylinder wall, which would damage the engine.

The three piston rings have names which explain their locations and primary missions.

Compression rings

The Top Ring and the Second Ring are closest to the top of the piston, and closest to the combustion process. These two piston rings are also known as Compression Rings, and they are there to seal the piston and keep the forces of combustion from getting past them. This allows all of the engine’s power to be used for moving the car forward, with none allowed to escape from the cylinder.

Oil ring

The third ring down from the top is called the Oil Ring, and it is located closest to the bottom of the piston. The Oil Ring’s job is to scrape the excess oil off of the cylinder wall on its downstroke, leaving enough oil for proper lubrication, while keeping too much from getting into the combustion chamber. This not only minimizes how much oil is burned, but also controls the oil consumption within the engine.

What are the signs of bad piston rings?

Bad piston rings are usually the result of wear, resulting in the loss of the tight seal between the piston and the cylinder. Wear of your piston rings can occur naturally over time, but it can be accelerated by improper maintenance. There can be several symptoms of bad piston rings. Let’s check them out:

• Excessive oil consumption: Bad piston rings can allow too much oil to get into the combustion chambers where it is then burned, along with the fuel-air mixture. This loss of oil will be noticeable as a steadily lower oil dipstick reading when you check your oil. Your dashboard low oil warning light may also illuminate, if your car has one. Top up your oil and call your mechanic.

• Gray/white/blue smoke from the exhaust: If you have bad piston rings, the oil from the crankcase could be getting past the pistons and into the combustion chamber, where it joins with the air-fuel mixture and is burned. The color and appearance of your exhaust likely indicates that you are burning oil. You may also notice increased oil consumption as noted above. Check your oil level and top it up as needed. Then get in touch with your mechanic and have the problem fixed, before you are cited by the police as a pollution hazard!

• Poor acceleration/loss of power: When you end up with bad piston rings, you are also losing engine compression. Because the seal between the pistons and cylinder walls has deteriorated, much of the power created in your combustion chambers is lost as it leaks out. Where does it go? Down the gap that is no longer sealed by the piston rings, and into the crankcase, contaminating your oil. This is known as “blow-by.” In addition to inadequate acceleration, you may notice hard starting, as well as greatly reduced performance overall. These symptoms appear at the late stages of a case of bad piston rings, and indicate that repairs should be made immediately, before more serious engine damage occurs. Let your mechanic know that you will be seeing him very soon.

• Engine overheating: This is what you can expect to happen when you have bad piston rings and ignore all of the other symptoms. Your excess oil consumption has sent your oil level into the danger zone, reducing engine lubrication, increasing friction and temperatures, and overloading your cooling system to the point where catastrophic engine damage is either about to happen, or has already happened. Your pistons can get so hot that they expand and scrape the cylinder walls, causing severe damage. The piston rings can break as well. And then there is the rest of your engine, which is also about to fail.

Should you drive your car with bad piston rings?

Only to the repair shop. If your car has bad piston rings, there could also be serious engine damage. Why make it worse by continuing to drive it? It is possible that your bad piston rings can be repaired before the problem gets any worse. Call your mechanic right away and have your car fixed.

How do you fix bad piston rings?

If your bad piston rings are caused by a sludge buildup inside your cylinders, and are not otherwise seriously worn, consider yourself lucky. Your mechanic may be able to use a special high-strength cleaner to clean your piston rings without taking your engine apart. If this is the case, you have just dodged a bullet!

If your bad piston rings are worn out, then things just got serious. Fixing bad piston rings requires disassembly of your engine, or its replacement. This is one of those repair jobs where the parts cost is not bad, but the labor cost will be eye-popping.

But there are some preliminary tests that can be done by your mechanic to determine the extent of the damage from bad piston rings, before it becomes necessary to take the engine apart:

• A compression test will check how well the piston rings are sealing the combustion chamber area

• A leakdown test will check if compression is escaping downward, past the piston rings, into the crankcase area A bore scope, inserted through each spark plug hole, will give visual evidence of physical damage inside the cylinders

If your car fails these tests, and the bad piston rings have been identified as the source of the problem, the next step is to take the engine apart, to the extent necessary to assess the damage.

When the damage has been fully revealed, an estimate of repair costs can be produced. The work required to repair the damage from bad piston rings can range from a mild engine rebuild to a partial (short-block) or a total engine replacement. Once you have this information, you will have a decision to make:

Is it worth repairing the damage from bad piston rings?

Let’s assume that your car is not covered under warranty (in which case you won’t have to pay for repairs). Here are some broad guidelines which can guide you as to what to do about bad piston rings, in consultation with your mechanic:

Do have your car repaired if: - It is fairly new and repairs are not too expensive - It is valuable and the repair cost is acceptable in light of that - It has sentimental value, you want to keep it, and you can afford to fix it

Don’t have your car repaired if: - It is old, has a lot of miles on it, and is not worth much - It is unreliable, costs a lot to keep running, and repairing a bad piston won’t change that - The cost of repairing it is close to or greater than your car’s value

If you decide not to have your car repaired, it is time to say goodbye. A car with bad piston rings is unlikely to be in acceptable running condition, so your only alternative may be to sell it to an automotive recycler or scrapyard, who will sell it for its parts and scrap value. Another option is to donate it to a charitable organization that is set up to accept this type of vehicle. You will get a tax deduction, and they will sell it to a recycler.

Can you replace bad piston rings by yourself?

Are you an experienced engine rebuilder? If not, the answer is NO! Replacing bad piston rings requires sophisticated skills and specialized tools. It’s not your average DIY job.

Bad piston rings can be prevented!

If you are reading this article because you already have bad piston rings, we feel your pain. But if you are here to learn, here’s a key takeaway: Preventing piston ring problems is much easier and less expensive than paying for an expensive repair (or junking your car) after it happens!

Do you happen to be one of those car owners who tries to save a few dollars by not getting your vehicle serviced, or doing any routine fluid checks? If that’s the case, you will eventually regret it. By not changing your oil, not checking your oil, and not paying attention to any of the warning signs, you will eventually be the unproud owner of a useless, worthless vehicle. The choice is yours.