* Fuel tank: This is the most serious scenario. Sugar can attract moisture and clump, potentially clogging fuel lines and injectors. This would lead to engine misfires, poor performance, and eventually, engine damage requiring expensive repairs. Getting sugar into the fuel system would be a very bad day.
* Engine compartment: Sugar, being hygroscopic (attracting moisture), could attract moisture and potentially cause corrosion on electrical components or metal parts over time. This is less immediate and drastic than the fuel tank scenario but still problematic.
* Interior: While a cup of sugar spilled in your car isn't a major mechanical issue, it's a significant mess. It's sticky, attracts ants, and will be difficult to clean completely.
In short: No, a cup of sugar won't instantly destroy your car. However, depending on where it ends up, it can cause serious and costly damage, especially if it gets into your fuel system.
