Freezing Point Of Diesel MERCEDES-BENZ C-Class Saloon (W204) (01.2007 - 01.2014)

Diesel fuel doesn’t freeze like water, but it does start to gel as temperatures drop, which can clog your fuel filters and stop the engine from running smoothly. For a 2013 Mercedes-Benz C-Class diesel, the critical temperature to watch out for is around 15°F (-9.5°C). Below this, the paraffin wax in diesel begins to crystallize, turning the fuel into a gel-like state that can block the flow to your engine.

To prevent this winter woe, many drivers use diesel anti-gel additives, which lower the gelling temperature and keep the fuel flowing. Adding these supplements as soon as cold weather hits—or even before when you expect a frost—can save you from getting stranded in icy conditions. Another tip is to fill up with winter-blend diesel if available, as it’s specially formulated for better cold-weather performance.

Also, keep your car in a garage where possible to reduce exposure to the cold and consider using a block heater to warm the engine and fuel system overnight on really chilly nights.

expect diesel to start gelling near -9.5°C, so anti-gel additives and winter diesel blends are your best friends to keep your Merc humming smoothly all winter long. ❄️🚗

Ready to prep your diesel beast for winter?

This question is very relevant! Your 2013 Mercedes C-Class diesel is vulnerable to cold.
Diesel Fuel Freezing Point
The main enemy is gelation (thickening), when paraffin clogs the filter:
- Summer diesel fuel: Begins to cloud (crystallize) at temperatures as low as 0°C (32°F) to -5°C (-5°F). Filter problems are likely at temperatures as low as -5°C (-10°F).
- Winter diesel fuel: Has a safety margin of up to -20°C (-28°F) to -35°C (-35°F), depending on the grade.

Precautions (2 main tips)
1. Switching to winter fuel:
- Always refuel with winter diesel fuel at reputable gas stations.
- Keep the tank as full as possible (this minimizes water condensation, which also freezes). 2. Using an anti-gel additive:
- Add an anti-gel additive (such as Liqui Moly Diesel Fliess-Fit) before the fuel becomes cloudy (ideal when refueling in warm weather).
- The anti-gel prevents freezing but does not defrost already thickened diesel fuel.
3. Maintenance: Replace the fuel filter before the season—an old one will clog much faster.