Quite often I encounter a vehicle that has exhaust with rather sharp smell similar to perfume. As far as I know this is attributed to the engine malfunctioning - normally working engine will exhaust gases without sharp smells.

What exactly causes the gasoline engine to produce exhaust with sharp perfume-like smell?

  • 1
    I have to admit that I read your question wrong at first. It read in my head as a proposal for a new perfume for ladies that would like to attract the attention of a motorhead. "Is that Eau de Racetrack?" ;-)
    – Bob Cross
    May 11, 2011 at 16:37
  • Wasn't it Harley-Davidson that did that one @Bob? :-)
    – Rory Alsop
    May 11, 2011 at 20:08

3 Answers 3


Most of the perfumes I know have a lot of carbon content (Alcohol based). So if I am to take a quick guess, this might be unburnt fuel being pumped out in gaseous form, a precursor to blackening of your tail pipes.

Or your vehicle might just be wooing the beetle behind - who knows? :)


If it's a sweet smell it might be antifreeze, although you'd usually get white smoke as well.

  • Emm.. How would antifreeze get into exhaust I wonder?
    – sharptooth
    May 30, 2011 at 6:53
  • 2
    From memory, I believe a leaking head gasket would allow coolant into the combustion chamber which would then make its way into the exhaust.
    – ManiacZX
    Jun 1, 2011 at 23:35

It's likely due to incomplete combustion, and the fact that synthetic perfumes are made from petrochemicals and have many components in common with gasoline, hence the sharp perfume-like odor. It's also a good reason not to overdo it with perfumes and fragrances - they really aren't good for anyone, especially not when inhaling them 24/7.

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