What is an evap leak?

An evaporative emission leak, also known as an EVAP leak, occurs when fuel vapor escapes from the fuel system and is released into the atmosphere instead of being stored in the vehicle's fuel tank. This can happen due to a variety of reasons, such as a loose or damaged gas cap, a cracked or deteriorated fuel line, or a faulty purge valve.

EVAP leaks can negatively impact a vehicle's performance and fuel efficiency, as well as increase harmful emissions that contribute to air pollution. In some cases, an EVAP leak can trigger the check engine light to come on in the dashboard.

To diagnose and repair an EVAP leak, a mechanic may conduct a smoke test to pinpoint the source of the leak and determine the appropriate course of action. This may involve replacing the damaged component, tightening the gas cap, or clearing any obstructions in the fuel system.

It is important to address an EVAP leak promptly to prevent further damage to the vehicle and ensure that it is operating efficiently and environmentally responsibly.