Wondering if you can drive with an EVAP leak?
The short answer is no.
While an EVAP leak will not pose an immediate safety risk, it can reduce your car’s fuel efficiency and affect engine performance if left unchecked. So, addressing the issue ASAP is necessary to prevent further vehicle damage.
But there’s more to it.
Read on to understand why you shouldn’t drive with an EVAP leak, five common signs that can help you identify a leak yourself, and how to fix it.
This Article Contains:
- Can You Drive with an EVAP Leak?
- 5 Symptoms that Indicate You Have an EVAP Leak
- Why Does an EVAP Leak Occur?
- How to Diagnose and Fix EVAP Leaks?
- 3 FAQs on EVAP Leaks
Let’s go!
Can You Drive with an EVAP Leak?
While driving with an EVAP leak is technically possible, it isn’t recommended.
Here’s why:
Your car’s Evaporative Emission Control System captures and stores vapors from the fuel tank and burns them in the combustion chamber during engine operation. This reduces air pollution by preventing the fuel vapor from escaping. However, when there’s a leak, these harmful fuel vapors can escape and pollute the environment.
The loss of fuel vapor also affects your car’s fuel efficiency, resulting in reduced mileage and increased emissions. This could cause your vehicle to fail an emissions test and damage your catalytic converter, resulting in costly repairs and hefty fines.
But how do you identify an EVAP leak?
Let’s find out.
5 Symptoms that Indicate You Have an EVAP Leak
Some common signs that can indicate potential problems with your EVAP system include:
1. Fuel Odor
When there’s an EVAP system leak, fuel vapors may escape from your fuel tank, making your car smell like gas.
Addressing this issue is important, as unaddressed fuel leaks can pose safety risks, including the potential for fire hazards.
2. Illuminated Check Engine Light
When the EVAP system’s leak detection pump senses a possible leak, it immediately turns on the check engine light.
However, the check engine light may illuminate for various other reasons, so it’s essential to confirm whether it’s caused by an evaporative emissions leak. You can use a diagnostic scan tool to identify the cause of the leak and get accurate repairs.
If an EVAP leak triggers your check engine light, the scan tool will display the following codes:
- P0440: Evaporative Emission Control System Malfunction
- P0442: Evaporative Emission Control System Leak Detected (Small Leak)
- P0456: EVAP System Leak
- P0457: Evaporative Emission System Leak Detected (Fuel Cap Loose/Off)
3. Poor Fuel Efficiency
If you notice your vehicle using more fuel than usual, it could mean there’s a problem with the EVAP system.
EVAP leaks allow unburned fuel vapors to escape, disrupting the air-fuel mixture and reducing combustion efficiency. When fuel vapors escape, they no longer get burned in the combustion chamber to propel the engine, resulting in poor fuel economy.
4. Engine Won’t Start or Idle Rough
The engine needs the right mix of air and fuel to start and run smoothly. A leak in the EVAP system can indirectly mess up the air-fuel balance needed for the engine to start smoothly, resulting in a rough idle.
5. Emissions Test Failure
The EVAP system is meant to capture the fuel vapor and prevent harmful emissions from being released into the atmosphere.
Leaks from the fuel system can increase the amount of pollutants your vehicle emits. As a result, your vehicle can fail an emissions test and you may end up paying a fine.
Next, let’s explore the causes of an EVAP leak.
Why Does an EVAP Leak Occur?
An EVAP leak typically stems from issues within the EVAP system components, such as:
- Deteriorated hoses and lines: Punctures, cracks, or wear in a vapor tube or rubber hose can release fuel vapors, causing a leak.
- Loose, damaged, or missing gas caps: A faulty gas cap can cause EVAP leaks by allowing gasoline vapor to escape from the gas tank.
- Faulty purge valve: A purge valve that’s stuck open can cause an EVAP or vacuum leak. A leak can also occur due to a damaged EVAP purge solenoid and its hoses.
- O-ring seal damage: The O-ring is crucial for sealing various components in the EVAP system, and any damage or wear to the ring can cause leaks.
- Damaged EVAP canister: The EVAP canister (also called charcoal canister) absorbs and stores gas vapors. Any damage to it can cause the gasoline vapor to escape.
Now that we know the causes of an EVAP leak, let’s look at some ways to confirm and fix it.
How to Diagnose and Fix EVAP Leaks?
Diagnosing issues with the EVAP system can be complex, so it’s recommended to consult a professional for repairs.
Here’s an overview of the steps a mechanic may take to perform an EVAP test:
- They’ll use an OBD-II scanner to retrieve the error codes that may have triggered your check engine light.
- If the code is related to the EVAP system, they’ll check the gas cap to ensure it’s tightened and look for signs of wear and damage. If the gas cap is cracked, they’ll replace it with a new one.
- They’ll inspect the purge valve and vent valve to see if they open and close properly and replace them if they’re stuck or not functioning as they should.
- They’ll also conduct a thorough visual inspection of every EVAP hose and the charcoal canister by looking for cracks and loose connections.
- Finally, they’ll use a smoke machine to perform a smoke test, which is a highly effective technique for identifying the location of the leak.
Once the cause of the EVAP leak is identified, the mechanic will make the repairs.
- In case of a small leak, they’ll clean any rust or corrosion from the affected components.
- For a large leak and irreparable damage, such as a leak in the fuel system, the mechanic will replace all damaged parts to ensure the EVAP system functions properly.
- They’ll conduct a follow-up to confirm if the repairs have been successful.
Got more doubts about EVAP leaks?
Let’s explore some other related queries.
3 FAQs on EVAP Leaks
Here are answers to some questions you may have about EVAP leaks:
1. How Much Will EVAP Leak Repair Services Cost?
EVAP leak repairs can cost around $100 to $600, depending on the severity of the leak, required repairs, and local labor charges.
Here are the estimated costs of repairing and replacing EVAP system components:
- Fuel cap: $10 to $60
- EVAP hose or line: $50 to $100
- Purge valve: $100 to $200
- Charcoal canister: $200 to $500
- Gas tank: $800 to $1500
2. Is it Safe to Drive By Fixing an EVAP Leak Temporarily?
While driving with temporary fixes for a small EVAP leak is possible, you should visit a mechanic for a more permanent solution.
Temporary fixes for a small EVAP leak may involve removing and reinstalling the gas cap or cleaning rust and corrosion off of the system components.
However, it might not be effective for a large leak and could lead to problems like the engine overheating or stalling, making it unsafe to drive. It’s crucial to have EVAP system leak repairs done by a professional to ensure your vehicle is safe for the environment and operates well in the long run.
3. Can an EVAP Leak Cause Engine Misfires?
Yes, an EVAP leak can cause engine misfires by disrupting the proper balance of air and fuel in the combustion chamber.
This disruption may result from issues such as a drop in fuel pressure or unwanted gas vapors entering the engine and interfering with the combustion process.
Keep Your Ride Eco-Friendly by Fixing EVAP Leaks
Addressing an evaporative emissions leak ensures your vehicle works well and minimizes air pollution. If you notice issues like poor fuel economy, rough idle, or an illuminated check engine light, it’s best to seek professional help.
And for that, you can reach out to AutoNation Mobile Service.
We’re a mobile auto repair and maintenance service that offers convenient bookings, upfront pricing, and a 12-month, 12,000-mile warranty.
Contact us to get EVAP repairs and replacements done from your driveway.