What are the signs that indicate the end of the lifespan of an air filter?

There are several signs that may indicate the need to replace an air filter:

1. Reduced engine performance: An old or clogged air filter may cause a reduction in engine performance due to insufficient clean air reaching the vehicle's engine.
2. Increased fuel consumption: An old or clogged air filter may lead to increased fuel consumption due to decreased combustion efficiency within the engine.
3. Increased noise level: An old or clogged air filter may lead to an increase in the noise level produced by the engine due to insufficient clean air being provided to the engine.
4. Exhaust odor: If the air filter has become damaged, old, or clogged, it may cause a foul odor to emanate from the vehicle's exhaust.
5. Poor performance: An old or clogged air filter may lead to poor vehicle performance due to insufficient clean air being provided to the engine.

It is important to refer to the vehicle owner's manual to determine the recommended interval for replacing the air filter, typically ranging from 10,000-15,000 kilometers or every two years.