6 Symptoms of Faulty Piston Rings
Is your engine burning oil, emitting blue smoke, or just not enough power? These are just a few of the signs that faulty piston rings can rob your engine of performance and cause oil loss and damage.
Faulty piston rings lose their ability to compress and seal, and if ignored, they will show noticeable symptoms that indicate a more serious problem. Read on to learn the obvious warning signs that your piston rings are losing their integrity.
Symptoms of Faulty Piston Rings
What’s noteworthy about the symptoms of faulty piston rings is that they are similar to the symptoms of faulty valve seals. However, you should always take your car to a repair shop to have it inspected. Here are the most common signs of defective piston rings:
1) Excessive exhaust smoke
Failed piston rings cause oil to flow downwards, resulting in smoke from burnt oil pouring out of the exhaust pipe. This smoke often appears blue or grey as the oil is burning inside the engine’s cylinders. During cold starts and hard acceleration, emissions worsen as oil tends to slip off the defective piston rings. Oil ingress not only increases oil consumption, but also impairs the optimal air-fuel ratio and combustion in each cylinder. When an oil-contaminated mixture is burned incompletely and inefficiently, more particles are released in the form of blue smoke.
Excessive exhaust smoke during acceleration or at high engine speeds indicates oil contamination in the cylinders due to poor piston ring sealing. Monitoring the exhaust gases directly indicates the condition of the piston rings and the amount of blow-by entering the combustion chamber.
2) Excessive oil ingestion
When a defective seal causes a large gap around the piston, engine oil can seep past the piston rings into the combustion chamber. This oil is burned during engine operation, resulting in increased oil consumption.
Even in engines with no visible oil leaks, if the ring seal fails, the oil will literally go up in smoke and cause extreme oil loss. Drivers will need to add engine oil more frequently to keep up with this type of increased consumption. Oil may need to be topped off every few weeks, but more frequently if the leak is severe. Therefore, it is important to monitor the oil level.
3) Poor Acceleration and Power Loss
One of the most noticeable symptoms of worn piston rings is loss of power. When piston rings lose their seal between the piston and cylinder wall, engine compression drops dramatically. This loss of compression causes the engine to produce less power.
Compression in the combustion chamber is important to generate the force needed to push the piston downward during the power stroke. Therefore, increased leakage across the rings and reduced cylinder pressure results in less pressure pushing against the piston surface. This directly reduces the power available to the connecting rods and crankshaft, resulting in reduced torque and engine power.
Drivers especially feel the loss of power when driving uphill or pulling heavy loads. The weakness of worn piston rings becomes apparent most quickly under challenging conditions. What once provided plenty of quick acceleration now feels sluggish and lackluster to the driver, no matter how hard he presses the gas pedal. Piston ring maintenance and diagnosis may help restore normal performance levels.
4) Engine Knocking or Ticking Noises
When piston rings wear out, the piston is no longer held tightly against the cylinder wall. This makes the piston more likely to rock back and forth and move sideways while the engine is running. This increased piston impact causes a knocking or ticking noise coming from the engine compartment.
The knocking noise tends to get louder as the engine warms up. The noise may come and go as operating conditions change. Severe piston knock may only occur under hard acceleration at first, but will get worse over time. This audible symptom calls attention to an underlying problem: piston ring failure.
Excessive piston slap increases the lateral load on the connecting rod bearings. Bearing wear can manifest in the form of an audible knocking sound at the bottom of the engine. If left unchecked, it can cause serious damage to the engine internals.
5) Excessive Oil Intake
Blow-by is when the air/oil mixture in the combustion chamber leaks past the piston rings, creating excess pressure in the crankcase.
This pressure is returned to the intake through the crankcase ventilation hose (PCV). If you have a lot of blow-by, you may notice that your intake feels quite oily.
6) Engine Overheating
Piston rings maintain pressure in the cylinder long enough for combustion. They also play a key role in oil management to properly lubricate the engine. If the rings lose their sealing force or tension, this oil control function will not work.
Incorrect oil management can result in insufficient lubrication of critical areas. This increased friction and loss of lubricating oil film promotes overheating of engine parts. It also creates hot spots. This means less air and oil movement and less efficient heat dissipation.
Additionally, more oil penetrating the combustion chamber dilutes the air-fuel mixture and reduces the cooling effect of fuel evaporation. The fuel cannot absorb the heat properly, causing internal temperatures to rise excessively.
Finally, loss of compression also means increased peak temperatures in the defective cylinder. All these effects of leaking piston rings lead to overheating and heat-related failures. Bearings wear out faster, seals harden and fail, and engine parts reach harmful temperatures.
These effects combine to contribute to engine overheating, which can cause permanent damage or catastrophic engine failure.