How To Test If Gas Cap Is Bad

The gas cap that you lot remove when filling up the fuel tank of your automobile can sometimes vesture out. This tin can lead to problems with the fuel in the tank and tin sometimes touch on engine performance.

As a full general rule, the symptoms of a bad gas cap include a smell of fuel from the vehicle, trouble removing or tightening the gas cap, a bank check engine light on the dashboard and water getting into the fuel tank.

Luckily, changing the gas cap is one of the easiest repair jobs y'all can carry out, once you have established that information technology is the gas cap that is at fault.

What Problems Can A Loose or Bad Gas Cap Cause?

The gas cap is often overlooked when it comes to problems with the fuel tank or a smell of fuel from the vehicle. Over fourth dimension, the rubber seals on the gas cap will harden and eventually habiliment out, causing information technology to fail.

A worn out gas cap won't seal the fuel tank as it should and this can lead to more serious engine performance problems if the fuel is constantly condign contaminated with dirt or water.

Here'south a more detailed caption of the symptoms of a bad or failing gas cap.

one. Odour of fuel from the exterior of the vehicle

A bad gas cap tin let fuel vapors to escape from the vehicle equally it no longer seals the tank as information technology should. This volition lead to the smell of gas around the outside of the vehicle and sometimes inside.

At that place are many other (more serious) reasons why fuel vapors are escaping from the fuel delivery organization of your car. Hither's a total article explaining why your car smells like gas that goes into more detail.

2. Check engine light

Sometimes a bad gas cap can cause problems with the fuel system on your auto. The fuel delivery system on modern cars is a complicated, highly pressurized organization that runs from the gas cap right through to the fuel injectors. If there is a problem anywhere in the fuel system then this volition lead to engine functioning problems and a check engine light flashing on the dashboard.

A bad gas cap can let dirt or water vapor into the gas tank, and this tin contaminate the fuel in the tank, leading to problems with the performance of the car. This can cause a bad fuel filter and tin can harm the fuel injectors if it happens regularly.

3. Various Emissions related Error Codes

If the gas cap is no longer sealing the gas tank and is allowing fuel vapor to escape, or contaminants to get in to the fuel, this will ordinarily lead to issues with the vehicle Evaporative Emission Organisation (EVAP).

The EVAP system fitted to modern vehicles is there to manage the evaporation of fuel fumes from the gas tank. If in that location is a leak (a bad or declining gas cap) then this volition trigger an error in the EVAP system that will exist stored in the ECU memory. An engine lawmaking error can lead to a check engine low-cal on the dashboard, or changes to how the engine performs.

Common EVAP related engine error codes are explained in detail in these other published articles, these include P0456, P0440, P0441, P0452 and P0455.

4. Poor fuel economy

A bad gas cap can lead to poor fuel economy. If the gas cap is not sealing the fuel tank, the fuel can go contaminated and in some cases fuel tin actually evaporate from the tank.

Fuel escaping from the tank is ordinarily only a problem for older cars, every bit newer tanks take i way systems fitted that volition forestall fuel and fuel vapors from escaping via a badly fitting gas cap. However, if the fuel is allowed to escape every bit vapor this volition lead to poorer fuel economy as fuel will be literally disappearing from the tank!

Contaminated fuel can also pb to poor fuel economy every bit the fuel injection management organization volition struggle to

5. Gas cap not plumbing equipment properly

It might seem obvious, but a very common sign of a bad gas cap is one that does not fit or tighten properly. This is more common on older vehicles, where gas caps were made from metallic rather than plastic, however it can notwithstanding be a problem with newer vehicles.

Newer gas caps are made from plastic and take rubber seals that ensure an air tight fit. Over fourth dimension, these seals can wear out by becoming difficult and brittle. They tin also get clogged up with clay and dried fuel (especially if it's a diesel fuel tank). These can all contribute to a gas cap that is difficult to fit or that won't tighten properly.

Next Steps

If it'due south obvious that the gas cap is damaged or is non tightening properly then you should start past replacing the cap with a new OEM replacement. Gas caps are cheap and you lot should always supplant i with a genuine OEM gas cap from a dealership.

If the gas cap doesn't await worn out and is tightening properly, so you probably have a problem elsewhere in the fuel system. If the vehicle is onetime (a archetype with a metal gas tank and gas cap) then it'southward always worth replacing the gas cap to begin with. Older metal caps don't seal as well as newer plastic versions, so information technology may non be obvious if there are issues with it.

If you have a newer vehicle, it'due south unlikely a bad gas cap volition cause major problems with how the engine performs, and information technology is less likely that the gas cap will go damaged to begin with.

Source: https://themotorguy.com/symptoms-of-a-bad-gas-cap/

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