Smell of gas in cabin during Las Vegas Summer

[Chang]

Hello everyone,

Have had our 2011 4.6L since 2015. It's nearing 140k miles.
Current issue we are having and have been having, is during the summer here in Vegas, when it's 105°F and above, after driving the car around for awhile, the cabin begins to reek of gas. The AC is definitely on during these hot months, but we also use it when it's 80 or 90 degrees out and don't notice any such smell.

We contacted a dealer years back when it first started and they said it was a defective design of the car and something they are aware of but offered no solution.

Mechanically-speaking, I'm pretty green so I'm unsure of where to even begin looking if I wanted to self-diagnose and attempt to remedy. I imagine start with fuel lines, exhaust system, AC components and so on.

But I was hoping someone may be aware of said issue and know of a remedy or at least point me in the right direction. We are getting to the point of considering selling the vehicle due to this issue, as the smell is becoming more and more obnoxious and will then linger in the garage if parked after driving in the high heat. We love the car and I have been able to tackle the few mechanical issues that have arose so sure wouldn't mind keeping her for lot longer if we can fix this.

Appreciate ya'lls time in advance. Thank you kindly.

 

[Gunkk]

There is a fuel tank access plate under the back seat. Yours is probably not sealed. Some RTV may get the job done.

 

[Chang]

There is a fuel tank access plate under the back seat. Yours is probably not sealed. Some RTV may get the job done.

Appreciate the response, ill give that a look see ASAP. Any thoughts on why this only happens when it's hot as hell? Never smell it in the cooler times. Maybe there's some science involved with the temp and seals and the escaping of vapors, etc...
Either way, I'll check out the plate and see if a little TLC does the trick after all

 

[Gunkk]

Any thoughts on why this only happens when it's hot as hell?

Gasoline evaporates at ambient temps, and at elevated temps it evaporates much faster and at greater pressure. So the hotter it gets, the higher the pressure will be in the tank at equilibrium.

Our cars have a charcoal vent canister that normally can handle regular conditions. But I would suspect that it may be less able to handle the higher evaporation rate above 40C (~105F).

Gas caps are also supposed to be vented to relieve excess pressure in the tank, so it might be worth trying a new one ($25) first, before resealing the metal plate under the back seat.