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November 16, 2009 4:55 PM

Why do I smell gasoline when I'm in my car?

I drive a 2003 Subaru Forester. Yesterday I started smelling gasoline inside the car. I haven't noticed any fluids or leaks under the vehicle, and the gas cap is tightly secured. My fuel needle doesn't seem to be dropping any faster than usual. I'm slightly past due for an oil change, taking it in for one this weekend. I've accidentally been a bit rough on my transmission and starter lately, grinding gears a bit harshly and quickly restarting the engine after a stall. These were brief but I'm paranoid because this is my first stick shift. Hopefully those are unrelated to the gas smell. I am mechanically uninclined.

I found this thread, which in interesting but beyond my level of car-maintenance skill. Any suggestions? How seriously should I treat this issue?

posted by The Winsome Parker Lewis to travel & transportation (17 comments total)

You could have gas vapors coming in through the air conditioning vents.

You could have stepped in a gas puddle at the gas station and tracked gas into your car, which gas has since been offgassing.

Any number of possibilities, really.
posted by dfriedman at 4:57 PM on November 16, 2009

Hmm, I'll be back at my car in a half hour and I'll sniff around and try to locate a source. Watch this space: I'll post what I find, if anything. My nose is okay at detecting smells, but ain't so good at the telemetry required to trace them, or whatever. ;-)
posted by The Winsome Parker Lewis at 5:05 PM on November 16, 2009

As to how seriously you should treat it: are you dizzy when sitting in your car from a lack of oxygen? If you are, then you need to treat it very seriously. If you are not, then the gas isn't present in sufficient quantities to affect your ability to stay conscious and drive.
posted by dfriedman at 5:09 PM on November 16, 2009

It's a very faint smell. It's just new, so I want to investigate thoroughly and make sure there's nothing wrong with the car. Or, you know, risk of imminent explosion.
posted by The Winsome Parker Lewis at 5:13 PM on November 16, 2009

Grinding gears should have nothing to do with anything. A few scenarios come to mind...

- you have a gas tank leak near the top of the tank which means you only have gas leaking when you fill up. Check for drips after your next fill up [oil change guys can likely look for this too]. This happened to me. Replacing the gas tank was not terribly expensive [$250?] as car repairs go
- you spilled gas on something which you then put in the car [this happens to me sometimes where I fill up, get a few drops of gas on me and flip out thinking something is very very wrong]
- there is some sort of hole in the fill-up tube that is somehow venting to your car. I have seen this in older Subarus with a lot of rust. This is not likely with your vintage but if your car is especially rusty, I'd think about this [and see if you can isolate the gas smell to even one side of the car]

Generally speaking gas smells, while worrisome, are likely not an imminent doom situation as long as they're not overpowering or there's gas leaking all over everything [i.e. in an obvious situation] in my personal non-mechanic position. It's worth paying attention to, but not freaking out over in my opinion.
posted by jessamyn at 5:21 PM on November 16, 2009

check out this thread. I recall having the same problem with a similar year forester...
posted by HuronBob at 5:23 PM on November 16, 2009

'bout a month ago I started smell gas in my 2003 Kia Sedona . . . took it in and it was the fuel pressure regulator . . . it had a leak and needed to be replaced. It was less than $200 fix.
posted by Sassyfras at 5:37 PM on November 16, 2009

It's a pretty common problem in Subarus (I had it, too, in a 2002 Impreza). There have been partial recalls and technical service advisory bulletins for certain models in certain years.
posted by iknowizbirfmark at 5:56 PM on November 16, 2009

When this happened in my car it was the oxygen sensor thingy that determined how much fuel to pull through. Bascially the engine was burning a bit rich so there was left over petrol. I could smell it through the air con vents, through the windows sometimes, and just generally vaguely hanging around the car, also sometimes I couldn't smell it at all. It wasn't a big deal, the smell or the sensor problem. The mechanic said we could get it fixed when we had time and it took us a small while to do so. I was going through more petrol though, not enough to notice over a small trip but definitely noticeable when I drove 500 kms. Didn't cost much to fix and paid for itself in increased fuel efficiency on the next out of town trip.

For my car this was something that needed a mechanic to diagnose (and triggered the check engine light actually). If the smell in yours doesn't go away or gets worse then definitely get it checked out, it could be something as easy as this or something else but just the smell isn't enough to know.
posted by shelleycat at 6:01 PM on November 16, 2009

The smell of gasoline can come from anywhere in the fuel system, from the gas tank, to the filler tube, gas lines, fuel pump, pressure regulator, fuel injectors, and all their connections. If you really want to find out where it's coming from, locate and sniff all those locations (and look for dripping gasoline). Otherwise, take it to a mechanic.
posted by exphysicist345 at 6:15 PM on November 16, 2009

Great, this was very helpful. When I got to my car earlier this evening I couldn't smell gas at all. I sniffed everywhere with the car off, and then started it up and continued sniffing the air vents and other spots as I drove across town. No smell. I'm always suspicious of car problems "fixing themselves" and the smell will likely come back. But you have given me some great direction for what to do when that happens. Thanks!
posted by The Winsome Parker Lewis at 6:55 PM on November 16, 2009

Is your check engine light on?
When you fill up your gas tank, do you fill until it *CLICKS* off by itself or do you top it up beyond that?

Manhandling the manual transmission isn't going to contribute to your fuel smell, although it will directly contribute to that burnt clutch smell.
A fuel leak or EVAP* leak will stink, however. Gasoline evaporates pretty quickly on a hot engine, so it may be difficult to pinpoint the location of the leak. It'd be best to take it to a mechanic who will check out the fuel system with the car running.

Pretty typically, a fuel smell is indicative of a fuel leak and that goes for any automotive fluid.
However, in some colder climates, drivers may complain of stinky fuel smells before the car is fully warmed up since cars will generally run rich (heavy on the fuel) until they're fully warmed up. If the fuel smell goes away rather quickly as you drive or if you only smell it in the morning, this may be the case. However, if the fuel smell persists throughout the duration of your trip, then you likely have either a leak or a rich mixture.



*The EVAP system in your car traps the fuel vapors that come from the gasoline in your tank. It stores those vapors in an activated charcoal canister (like big Brita filter) and then purges those vapors into your engine via a computer controlled valve. It uses a simple low-pressure pump and switch sensor to determine if there's a leak in the system. Hence, the check engine light when you leave your filler cap off. A leak in this system will cause a fuel smell and a check engine light. Overfilling your fuel tank can result in saturating the charcoal canister with liquid fuel and the system will inadvertently purge that liquid gas into the engine, causing a fuel smell and a rich mixture.
posted by Jon-o at 7:02 PM on November 16, 2009

Well in my case it turned out to be about 800 bucks worth of needing your fuel pump replaced. Worked a treat.
posted by nanojath at 7:30 PM on November 16, 2009

I had a gas smell in my 2000 Jetta and it turned out to be a leak in my fuel line. Not cheap. But definitely worth fixing because it was a fire hazard.

Ironically, the loaner they gave me while they were fixing caught on fire an hour after I brought it home, but that's another story entirely.
posted by radioamy at 8:34 PM on November 16, 2009 [1 favorite]

Jon-o: A very informative response. My check engine light is not on. I only fill until the pump clicks off by itself (I used to top it off to an even dollar amount with my old vehicle, but the Subaru has broken me of the habit as it overflows with even the slightest extra amount).

I've only smelled the burning clutch smell a couple times when I was particularly clumsy, still learning to drive stick, and it struck fear into my heart. I don't know how to gauge the remaining life of my clutch but that awful smell made me worry I almost killed it right then and there. I hope it's safe to drive still and won't suddenly die on me without warning.

nanojath: Ouch! That's really a lot more money than I can afford at the moment. I'm crossing my fingers that it won't turn out to be anything so expensive.

radioamy: HOLY CRAP! Glad no one was hurt (I think)!
posted by The Winsome Parker Lewis at 7:34 AM on November 17, 2009

I hope it's safe to drive still and won't suddenly die on me without warning.
Don't worry. It'll give you plenty of noisy warning and it takes ALOT of abuse to shave significant life off of your clutch.
posted by Jon-o at 5:11 PM on November 17, 2009

I sent you a MeFi Mail just in case you don't read this, but I've got some really important information to add to this.
In the past week, I made two identical repairs to Subarus that are about as old as yours.
There is a two-inch piece of fuel hose on the drivers side of the engine that carries fuel from the metal fuel supply line to the fuel rail. On both of these cars, that piece of hose had deteriorated and started to leak fuel. The fuel collects on the engine (since it's a flat-four, not in-line) and you won't see a puddle on the ground.
I'm finding it to be a pretty common problem on Subarus. The hose is cheap enough, but it takes about an hour, hour-and-a-half of labor to unbolt enough stuff to get enough slack to get the hose out.
I know it's been more than a month since you asked this question, but if the fuel smell is still there, take it to a garage immediately. I'd be willing to bet that you have a fuel leak.
posted by Jon-o at 2:21 PM on January 3