I object even more to the variation "like a sweating engine working hard" -- it isn't parallel... or however the right way to say it is. Like I said, my brain isn't what it used to be. But it doesn't point intelligently at any part of the sentence. You are comparing the scent to sweat. Although even that has me itching to have a more functional brain... Maybe something like The sweat of an engine working hard is a lingering scent of gas and burnt oil. Or A hard-working engine has its own sweat, leaving a lingering scent of gas and burnt oil.
But of course looking at it out of context makes it more difficult to provide intelligent feedback.
I also haven't read enough of your writing to know your voice. There is no skill more important in an editor than the ability to hone a writer's own voice, rather than replace it with the editor's voice. I need to read more volume to be able to comment within your voice.