Piston Ring Wear in an Engine

In this article in our vehicle maintenance and repair corner, we’ll talk about piston rings. Even though piston rings may seem like small, unimportant parts, they’re vital to the engine. If piston rings wear out or fail in an engine, it can lead to problems severe enough to leave your vehicle stranded on the road.

At the mildest, your car’s engine may become excessively noisy. Now let’s look at the causes of piston ring wear in an engine, how to tell that a ring has worn out, and what can happen if the rings wear out.

piston ring wear in an engine and pistons

How Can You Tell There’s Piston Ring Wear in an Engine?

If an engine’s rings are severely worn, this can be quickly confirmed with the dipstick and oil filler cap test. If you see visible smoke when pulling out the dipstick, if the dipstick seems to pop back up when it’s not fully seated in its tube, or if the oil filler cap jumps up when removed and placed loosely over the opening, that vehicle has wear in its piston rings, pistons, or cylinder liners.

how to tell there is piston ring wear in an engine, black smoke from a car

Also, if excessive black smoke comes out of the exhaust when the throttle is pressed, that’s another sign of wear — the vehicle is burning oil, the oil level will drop noticeably, and the vehicle’s oil should be checked constantly.

Engine Sound With Piston Ring Wear

You can click the play icon to listen to the sound an engine makes with piston ring wear. (above)

Sign of Oil Consumption

Worn piston rings let oil leak into the combustion chamber, increasing engine oil consumption.

Blue Exhaust Smoke

Bluish smoke from the exhaust is a classic sign of oil burning caused by piston ring wear.

Loss of Compression

Worn piston rings cause a drop in cylinder compression and reduced engine performance.

The Cause of Piston Ring Wear in an Engine

In a new engine, this can result from incorrect assembly or a metallurgical defect.

The clearance between the ring and its groove in the piston is very important for healthy operation and staying clean. If the ring’s movement is even partially restricted, the lubrication regime breaks down, oil stays on the surfaces longer, and burns locally.

Over time, a very hard carbon buildup forms in the piston ring grooves. Eventually, the ring’s small but vital movement on the piston is completely blocked. A ring that becomes immobile either breaks or seizes. At high speeds, seizing to the cylinder doesn’t happen outright; instead, small localized welding and tearing events occur on the cylinder surface. Once the geometry is distorted, the ring breaks.

In an engine used at low speeds, the carbon buildup keeps growing until it fills the space between the piston and cylinder. This buildup, harder than the metal itself, polishes the cylinder surface through the piston’s motion. This polished cylinder surface, along with the ring, eventually loses the ability to hold oil. Seizing or locking up happens through this or a similar scenario.

What Does Piston Ring Wear in an Engine Lead To

Piston rings are among the most important moving parts inside the engine that provide compression. If piston ring wear occurs in an engine, it will bring along many undesirable consequences.

Wear is generally highest in what we call the top compression ring; as the rings wear, engine power drops and the engine starts burning oil.
See also: Why Does an Engine Burn Too Much Oil

What Should Be Done to Prevent Piston Ring Wear in an Engine?

To minimize piston ring wear in an engine:
The correct engine oil should be chosen.
See also: How Is Engine Oil Selection Done?
Engine oil change intervals should be observed.
See also: Vehicle Parts Inspection and Replacement Schedules
The vehicle should be driven with varying engine speed. We should constantly check the vehicle’s coolant and take care that the engine doesn’t overheat.