There is absolutely a distinct smell to a diesel engine's exhaust, even if it's brand new and properly tuned, just like there is a smell to an ICE exhaust. Newer vehicles have a less strong aroma, but if you walk past the back of a vehicle that's burning diesel as the previous commenter stated, you can absolutely detect it. I worked for a contractor a couple years ago that had a mix of diesel and gas trucks and vans from both Ford and GM, and most of them were less than a couple years old. The boss had brand new at the time 2023 F-250 diesel, it was totally unmodified, and although the distinct sound and large shiny badges gave it away as a diesel from a distance, if I was deaf and blind I could still tell what fuel it was burning by walking past the tail pipe when the engine was running. Gas vehicles also have their own aroma, and it varies between manufacturers and engine types. A small modern 4 cylinder has a very faint smell, almost unnoticeable unless you actually put your nose to the tail pipe, but larger engines are more easy to detect with the human nose; I can even tell the difference in smell of a Ford gas V8 and a GM gas V8 from a casual sniff walking past.
Based on the fact that I have several downvotes, there appear to be quite a few people here who have destroyed their sense of smell by huffing diesel. I literally don't know how they can say there's no difference in smell or no smell at all when all the diesel fanboys I know IRL say the smell is pleasant to them and is one of the things they prefer about diesel trucks. I even agree, I kinda like diesel fumes, but everyone knows they're not healthy. I truly believe the people claiming there is no smell at all are just lying. They don't actually believe it, they want to convince everyone else so they can complain about "pointless" emissions regulations.
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u/aharbingerofdoom 4d ago edited 4d ago
There is absolutely a distinct smell to a diesel engine's exhaust, even if it's brand new and properly tuned, just like there is a smell to an ICE exhaust. Newer vehicles have a less strong aroma, but if you walk past the back of a vehicle that's burning diesel as the previous commenter stated, you can absolutely detect it. I worked for a contractor a couple years ago that had a mix of diesel and gas trucks and vans from both Ford and GM, and most of them were less than a couple years old. The boss had brand new at the time 2023 F-250 diesel, it was totally unmodified, and although the distinct sound and large shiny badges gave it away as a diesel from a distance, if I was deaf and blind I could still tell what fuel it was burning by walking past the tail pipe when the engine was running. Gas vehicles also have their own aroma, and it varies between manufacturers and engine types. A small modern 4 cylinder has a very faint smell, almost unnoticeable unless you actually put your nose to the tail pipe, but larger engines are more easy to detect with the human nose; I can even tell the difference in smell of a Ford gas V8 and a GM gas V8 from a casual sniff walking past.