I noticed this two times now on a long trip when going at highway speeds and climbing a long hill I get a sulfury smell coming in the vents (I THINK) and I assume is exhaust. I wonder if anyone has experienced this is if so what was the cause and cure. In my head I am thinking that something has come loose at the fire wall and is allowing the fumes to enter the cabin via the climate contol system!
The 1st time it happened my co pilot looked over at me and said "was that you?" LOL

 

If I remember correctly, it's your catalytic converter. Usually they will make a fart smell when they are going bad.

Although I've never heard of it coming through the vents, you might want to call a couple of mechanics and find out what they think.

That's my guess anyway.

 

i dont believe that completely as my mother had a 73 mazda that always smelled that way.......and i have little faith in MOST "mechanics" sorry to say, however its going to the volvo dealer soon for brake and front end work , and I will mention it to them in case it IS a cat problem and is covered by my VERY expensive power train warrentee LOL

 

Like I said, just a guess. That's the only thing I could think of.

Good luck with it. I hope it's something that is easily fixable!

 

Depending on your mileage on the car, the exhaust has springs holding it on the engine. When the exhaust pressure gets too high it will blow past the gaskets. My guess is that the catalytic converter is getting plugged... or the exhaust (but not likely) and needs to be flow pressure tested and/or replaced. Catalytic converters don't last much longer than spark plugs... especially in high mileage cars. I replace my catalytic converters every 125k usually. Turbo cars need a special one costing a bit more... around $300.00 but it saves the motor and way better mileage from the replacement... Good luck! Russ

Just a thought... check the seal around your tail gate door... and adjustment!