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2011 Hyundai Santa Fe - Diesel smells like gas

I have a diesel engine. When stopped and idling there is a slight smell of gas that comes through the air vents. The smell is like bottled gas, I don’t mean a smell of petrol or diesel. I have had the exhaust pipe and tubes inspected by two independent garages and they can’t find a fault. Any ideas what this could be? Thanks. - Mark.

How long has this been going on? If it’s very recent, you might have just gotten gas on something the last time you filled up, and the only time you smell it is when there isn’t any airflow over the car.

Thanks for your reply shadowfax. I did think exactly what you suggest but smell has been persistent for 3 months. However I’m starting to get to the answer. 3 garages have said that they can’t find a fault, but the third garage, a Hyundai specialist has told me what they think the cause of the problem is.

Two months ago I got new tyres fitted on the front of the vehicle. Hyundai have told me that I should also have the tyres replaced on the rear because if there is a difference in tread thickness by more than 3mm then this causes a problem to the 4WD differential system. As the front tyres have a bigger diameter than the rear, the rear tyres will have to rotate faster. Apparently the smell is coming from the burning of the differential clutch. I don’t know if this is true, but I did google it and it seems that it might be true. I will replace the rear tyres and report back.

Thanks for taking an interest!


I don’t what tire shop you used but don’t use them again. Anytime only 2 tires are mounted they should go on the rear . Also they should have told you that with All Wheel Drive ( I think that is what you have not 4 WD system ). Just for reference where are you located?

Thanks. Yes, it is all wheel drive like you say. I had no idea about this and neither did the tyre shop. I also found out that they should go on the back, so I swapped them 2 days ago but the smell persists. I will get two more new tyres. Hopefully there is no permanent damage.

just for reference where are you located

I’m in the UK.


So much important information in owners manuals goes unheeded by owners. But tire shops ought to have some idea what kind of drive train is on the car they are working on, and at least advise the owner there’s a possible problem. If the owner then says “go ahead” the shop can decide what to do next.