My daughter's 2005 Monte Carlo has a strong odor of gasoline both in and outside of the car when her fuel level gets to about a quarter of a tank. A mechanic had previously said there wasn't a leak and it was just a filter that gets clogged. She is out of state at college and I'm trying to keep her from getting ripped off by a mechanic telling her it is something more expensive than what it actually is. Any help would be greatly appreciated.

 

Gas leaks are never easy....
Could be a clogged Gas filter....Even though it still runs...
with the minimal info you have given..it makes it kinda touigh to figure out!
Like Motor, mileage, state your from...etc...
It could be a multitude of things...But if your smelling it inside and out...
I would check under the hood for starters...Sometimes the high fuel pressure line that feeds the fuel rails tend to leak..especially on a low tank and the pump has to work harder thus increaseing fuel pressure..(its never good to run your tank down below 1/4 a tank...try to keep these montes pretty much at 1/2 tank or more....

Maybe theres a fuel line thats rusted thru and just dont notice it til you see your getting low on fuel...Like i said without more pertinent info...Its anybodys guess...

I would definately start with a new fuel filter...
and then have or check all the fuel lines yourself for a leak...
Its a starting point....
How far from home at college is she?...To far to possibly swap vehicles with her til you get her leak resolved?

Maybe someone else will chime in with a few ideas as well...

 

I had the same thing on a 97 Chevy Lumina, God rest it's soul in the junk yard now, that had a strong gas smell and one day I look and look around and found that the gas fuel injection regulator was wet with gas.
If there is a hint of a gas smell anywhere get it fixed A.S.A.P. because you don't want a fire anywhere in your car.
Besides ? a leaky gas fuel injection regulator will give you bad gas mileage.
They run about $ 50 depending in what area of the country you live and never get one from the junk yard because you will never get the old O-ring seal to seal right.... even if you bought a new one and removed it to work on the intake.
It sort of looks like a Top Hat on one of the corners of the plentum.
Another area of gas leaks are the fuel injectors O-ring seals, once again get that fixed A.S.A.P.
Check all of your connections to your fuel lines and check to see if they are not rusted through under the car.
Another area of gas smells is the vapors coming from the gas tank.
Check to make sure the gas cap is tight and in good working order.

 

When I bought my 2003 Monte 2 days later I was looking under the hood thinking, I sure hope that gas regulator does not leak because I am hurting for money.
Well, as Murphy s Law works, just a day later I looked under the hood and sure enough the gas regulator was wet and leaking and I needed to replace it A.S.A.P. so I won't have a fire under the hood.
When you do replace the gas regulator you will have to remove the throttle body and that's a good time to clean the throttle body and check the EGR valve.
Yes, you will have to buy a new throttle body gasket but they are not expensive, that is ? if you can find a auto parts store that has then.
I had to go to 3 or 4 different auto parts stores to find one.
If you do have someone replace the gas regulator for you best thing to do is take the old one off and take it to a bench to get the large nut off the bottom, never do it while it's on the car or you can damage or bend the fuel rails.
The bolt to loosen the bracket for the fuel lines is a pain to work with.
Get a fuel line disconnect kit to disconnect the fuel lines, that are not expensive if you buy it at Harbor Freight.

 

Sorry if my post was sort of confusing, that was working with a 3.1. L engine, or a 3.4 L engine.
On a 3.8 the fuel regulator is about 1/3 almost in the middle of the plastic intake plentum from looking from the right.
It's held in with a C-clip.
If it's a 3.8 L engine make sure you release the fuel pressure from the lines before you take the old fuel regulator out or you will have gas all over you.
One again the ones on the 3.8 L run about $ 50-60.
Those fuel regulators on the 3.8 L engine are much more easier to replace.
You don't have to remove the throttle body on the 3.8 L engines to get to the fuel regulators.