Q: I have a 2001 Subaru Forrester. For a couple of years now, I have had this terrible gas odor only in the cold weather and usually when I put the heat on. Several people have looked at it and no one seems to know the cause. It can be pretty bad at times. Sometimes it smells like it’s burning, too. I would have it looked at again, but don’t want to spend money for someone to tell me they don’t know what it is. Any suggestions?
A: My first suggestion is to continue pursuing this problem. A few common places for leaks that are hard to find would be the top of the gas tank, a porous diaphragm at the fuel pressure regulator, a leaking vent hose at the filler neck and also the fuel tank filler neck itself. It’s interesting that you did not mention a Check Engine light. Your vehicle is equipped with the OBD II computer diagnostic system. One of the major functions of this system is to check for fuel vapor leaks.
I would be more inclined to look under the hood for this leak if the back underside looks OK. The reason is that you say it’s worse in cold weather. In cold weather, you are using the vehicle heater at a higher fan speed. The air intake for the HVAC system is located near the engine compartment, so you could have been pulling in fumes from the engine. However, you need to be sure it’s really gasoline you are smelling and not antifreeze from a leaking heater core.
And finally, you didn’t mention any loss of antifreeze, but your car has a reputation for blowing head gaskets, which will make a horrendous smell when leaking externally from the gasket and hitting the exhaust pipe. Don’t let this go. This could be very dangerous.