What would happen if the piston rings do not seal properly?

When piston rings do not seal properly, it results in increased blow-by. Blow-by refers to the escape of combustion gases past the piston into the crankcase. This phenomenon occurs when there are gaps in the sealing capability of the piston rings, allowing pressure from the combustion chamber to bypass the piston.

The primary role of the piston rings is to create a tight seal that keeps the combustion gases contained within the cylinder during the power stroke of the engine. Proper sealing is crucial for maintaining engine efficiency, power output, and preventing oil contamination. When blow-by occurs, it not only leads to a loss of engine power and efficiency but can also allow unburned fuel to escape into the crankcase, leading to further operational issues.

In contrast to the other options, which suggest improved performance in terms of cooling, efficiency, or fuel mixture, the reality is that poor sealing due to faulty piston rings directly correlates with a problem in engine performance and increased emissions, making the correct outcome the increased blow-by.