Diesel fuel contains paraffin. When temperature drops, the paraffin forms small crystals. The crystals clog the fuel filter. The engine then fails to start or stalls on the road.
This happens even when the tank holds fuel. A diesel's cold resistance depends on its grade. Even with a healthy engine, the wrong fuel can stop the truck. So choose fuel to match the season.
When you pick diesel by grade, two figures matter: cloud point and cold filter plugging point. At the cloud point, the fuel turns hazy and paraffin starts to separate. At the plugging point, the filter starts to clog. For the driver, the second figure matters more. If the truck cannot filter fuel below that temperature, the engine stops.
Fuel is graded by cold resistance: summer, winter, and arctic. Summer diesel starts to gel at a noticeably higher temperature. Winter diesel is built for low temperatures. Arctic diesel handles the hardest frost.
The fuel data sheet lists the cold filter plugging point (CFPP). Choose fuel with that figure below the lowest temperature you expect. If summer fuel is still in the tank, replace it before the cold arrives or blend it with winter fuel.
Cold varies by region. Tashkent and the Fergana Valley are milder than the northern areas, Karakalpakstan and Khorezm. If your route crosses a colder region, choose fuel for the lowest temperature you expect. When you refuel along the way, ask for the grade there too. Mixing different fuels on one route can cause problems.
Water in the fuel can freeze and block the filter. Drain the water separator regularly. Change the filter on schedule. If the truck has a filter heater, check that it works.
A full tank reduces condensation. Moisture collects on the walls of an empty tank and turns into water. Fuel up at trusted stations. Cheap fuel from an unknown source can cause problems.
Anti-gel additives raise the cold resistance of the fuel. Add them before the fuel gets cold and follow the instructions. An additive will not fix fuel that has already gelled. Ask a service center whether an additive suits your truck.
Before a cold start, check the battery and glow plugs. Let the engine warm up for a few minutes. Never heat a frozen filter with an open flame, because it is dangerous. To prepare for winter, book service at faw.uz/en/services/, and find dealer contacts at faw.uz/en/dealers/.
Plan your fuel supply before winter. Set a date in autumn for the switch to winter diesel. Ask the fuel station for the grade and get the data sheet. Move all trucks to the same type of fuel. That reduces the problem of mixed fuel.
Stock spare filters and water separator parts in the warehouse. If a filter clogs on a cold day, little time remains for the replacement. Keep trucks in covered space where possible. Give drivers a short briefing: keep the tank full, check the water separator, and follow the cold start routine.
Watch the weather forecast. If a sharp cold snap is expected, check the fuel and filter before trips. Build engine warm-up time into the plan before departure. The driver should know whom to call when a problem appears. For service contacts and winter preparation, see faw.uz/en/services/.