Why does my heater smell like gas in my car

x2 on the exhaust leak. That or a fuel leak, under the hood. Most vehicles have their fresh air intake below the windshield, above the engine bay area. If there is something leaking under there then it can get pulled into the fresh air stream and enter the vehicle.

Check for a fuel leak at all fuel connections/hoses under the hood. To check for an exhaust leak, I recommend using Seafoam (intake manifold method) which will turn the exhaust white and show where it is leaking under the hood. A lot of times some exhaust will leak from where the manifold(s) meet the head(s), if you have an excessive leak you may need to tighten up manifold bolts or replace the gasket between the head and the manifold.

Does it only happen in heavy traffic or even when there are no other cars nearby?

Thanks for the answers so far. - If it's an exhaust leak... then wouldn't it also smell when pulling air in summer, like for A/C ? Or is that a different air intake? Is there any danger in leaving this unfixed? I've asked Gary's Automotive to take a look while I had my brakes changed but they couldn't find any fuel smell with the car not running, but who knows how thorough they were...

- It happens regardless of if there's other cars around. If I'm driving on the highway though it doesn't happen (I'm guessing the air rushing by prevents the smell from being pulled in?). But as soon as I'm idling at a stop or start driving slower, the smell is present.

fuel pump ? the fuel pump for most mports are usually under the rear seat/ trunk area.

I've had that same problem long time ago in my 86 Buick Century, it turned out to be a fuel leak. It’s something you definitely want to fix as soon as possible, it is a fire hazard, not to mention you’re wasting fuel

Zedix wrote: ↑Thanks for the answers so far.

- If it's an exhaust leak... then wouldn't it also smell when pulling air in summer, like for A/C ? Or is that a different air intake? Is there any danger in leaving this unfixed? I've asked Gary's Automotive to take a look while I had my brakes changed but they couldn't find any fuel smell with the car not running, but who knows how thorough they were...

- It happens regardless of if there's other cars around. If I'm driving on the highway though it doesn't happen (I'm guessing the air rushing by prevents the smell from being pulled in?). But as soon as I'm idling at a stop or start driving slower, the smell is present.

I hate to say this but, I am not a fan of Gary's Automotive. There is a really good shop in Orleans, Precision Automotive, http://www.orleansonline.ca/Precision/index.htm. The shop is good, modern and has all the electronic tools needed to work on almost all makes. Another place I am familiar with that has a very good reputation is Orleans Auto Tech http://www.orleansauto.aaro.ca/. They have been around for a long time and everyone I know that goes there swears by them.

Thanks Pete_Coach, you actually answered my next question, which was going to be if anyone recommended any garages that would be able to look into this. After my last experience with Gary's, and hearing of my friend's, I think this was my last trip to their garage. It's convenient because they have a location in Kanata where I work so I can simply drop off my car in the morning and pick it up after work, which is why I went there... I might have the car checked on a weekend at one of those two places, after Christmas - I'll give them a call for sure, thanks. After all the car has been doing this for as long as I can remember (3rd winter now...) so I'm sure the problem isn't going to get worse (knock on wood). As far as I know, the problem goes away: - When driving at higher speeds - When *not* using the heating, or re-circulating the air - As soon as the temperature outside warms up... I can't figure out if the cold weather is triggering this behavior, or if it's because it coincides with the fact that cold = using the heater!

My suspicion however is that it has to do with the cold weather... Maybe the cold is making a certain part shrink, which enlarges a crack or makes something loose, then the problem shows up... As soon as ~March shows up the problem goes away every year, and comes back in December! Just some guesses though, I still don't know much about the mechanics of cars haha

I am sorry, I don't know any shops at that end of town and Orleans is a long way to drive to have something checked out.
You could have a fuel filter that is dirty and bypassing too. Any driveability problems? You will get more fuel smell in the winter simply because it does not evaporate and dissipate quickly in the cold. Gas is one of those fluids that is very intense, one drop is enough for you to smell. I don't know your car but there can be any number of places were vapours can escape/