An EVAP leak occurs when the emission control system in a vehicle is defective.

In this particular part of the vehicle, the gas vapors remain trapped in the gas tank. If there is a leak, these vapors are released into the atmosphere and cause air pollution.

Although it is technically safe to drive with an EVAP leak, there are certain things you should be aware of. This is a major problem that needs to be addressed for a number of reasons.

Causes of EVAP Leak

A possible cause of EVAP leakage is if the hoses that transport the gas vapors to the engine are damaged. Although these hoses are usually quite durable, they can wear out over time. Regular wear and tear will result in a leak if the damage is not repaired or replaced.

This type of leak can also occur when the coal canister is worn or damaged by blunt force. Steam can rise up even through very small cracks. If the canister has cracks, you must pay for a full replacement.

In rather rare cases, a defective purge or bleed control valve may be the cause. If one of these valves gets stuck for any reason, they cannot do what they were designed to do. This can lead to gas vapor leakage, but it does not happen very often.

Believe it or not, a simple loose cap on the fuel tank is usually the reason for an EVAP leak. Whether the cap is broken or you have simply not put it back on properly, you should check this before doing anything else.

Signs Your Vehicle May Have an EVAP Leak

First, you must be aware of the signs of an EVAP leak so that you can quickly identify the problem.

1. Check Engine Light

One of the first signs of an EVAP leak is the check engine light on the dashboard. There can be many reasons for this, but it is a common symptom that you should be aware of. It is important that you have your car checked whenever you see this light come on. Make sure that the fuel tank cap is in place all the way up. If the cap is loose at all, you may receive this notification on the dashboard to have the engine checked.

2. Fuel Odor

Some vehicles that have this type of leak produce a distinct fuel odour. This all depends on the type of car you drive, but it is something you should be aware of. This is more common in older cars, but it is still possible in newer models.

3. Lower Gas Mileage

If your vehicle no longer seems to achieve its usual fuel efficiency, you may have an EVAP leak. The mileage of a car tends to decrease slowly over time, but with this type of problem it decreases much faster. This is something you should notice fairly quickly.

4. Odd Sounds

If you have an EVAP leak, you may notice a strange banging or clicking sound from your vehicle. This happens when the 3- or 2-way EVAP valve cannot function properly. It constantly tries to pressurize the fuel tank, which leads to these clicking noises from the solenoid valve. It may be faint at first, but it will probably click faster the longer you drive without solving the problem.

Mechanic Engine Bay

Is it safe to drive with an EVAP Leak?

While it is not dangerous to drive around with an EVAP leak, there are a number of good reasons to avoid it. The first reason is that you will harm the environment. Your car will emit exhaust fumes, which will contribute to the destruction of the ozone layer.

If you live in a state that requires emission testing, you will fail if you don’t fix the leak. This may result in you having to pay a fine or simply not being able to renew the registration of your car. An EVAP leak will prevent you from passing this test.

Diagnosing an EVAP Leak

There are ways to diagnose an EVAP leak without taking your vehicle to a mechanic. The first and easiest way is to simply check your fuel cap. If the fuel cap is not fully tightened, you just have to put it on properly. This could solve the problem immediately.

If the fuel cap is not the problem, you can use a scanning tool. These tools can be quite expensive, but it is worth the effort. With such a tool you can search for specific errors that are associated with specific problems.

For example, a “P0440” code means that you have a faulty evaporative emission control system. There is also a “P0442” code that indicates a leak in your EVAP system. If you want to save yourself some time and inconvenience, this tool can be very useful.

Cost of Fixing an EVAP Leak

The cost to repair an EVAP leak can range from about $100 to over $500. This depends largely on the cause of the leak and the location where the work is to be done. Some causes require only minor repair work, while others require replacement parts. The design of your vehicle is something else that affects how much you pay.

If you have this type of leak due to damaged parts, it is usually better to simply have them replaced. Repair work is usually less expensive, but the problem could reoccur in the near future. You should listen to your mechanic’s recommendation before making a decision. If you spend more in the short term, you can save money later.

Some people postpone fixing their EVAP leak because it’s not necessarily dangerous, but it’s still something you should get fixed as soon as possible. Leaking gas fumes from your vehicle is bad for the environment and can lead to fines.