Piston liners and rings are located within the cylinders of your primary engine block. They keep dangerous gases from escaping from the combustion chamber. They also aid in the regulation of your engine's temperature. Piston liners are used by manufacturers to create a space that allows each piston to move up and down. The liner is subjected to constant force and high temperatures (over 2000 °C). As a result, the liner will deteriorate over time. Some (but not all) engines can have worn piston liners replaced. You should therefore ensure that this is possible on your vehicle before purchasing it. Overheating, stalling, and starting problems are all signs of worn piston liners. However, the last two symptoms may indicate that the pistons themselves are worn and need to be replaced. Piston rings are typically sold in three-packs. Between the engine piston and the liner, these rings form an airtight seal. Despite its small size, each piston ring is critical in keeping oil out of the engine cylinders, even under high pressure. Each piston ring also aids in the containment of fuel, allowing the combustion process to do its work. Piston rings will wear out over time as a result of these harsh conditions. Excessive oil consumption and white or grey exhaust smoke are signs of worn piston rings.