What is winter diesel and how is it different?

Winter diesel has anti-freeze additives that lower its CFPP (Cold Filter Plugging Point) from -10°C to -20°C, per EN 590 standard during the cold period (16 November – 28 February in Romania). This prevents diesel thickening and fuel filter clogging in freezing weather.

Do I pay more for winter diesel?

No. Winter diesel costs the same as standard diesel. The switchover happens automatically at the refinery from 16 November through 28 February. The anti-freeze benefit is included in the standard price at no extra cost to consumers.

How much more fuel do I use in winter?

Winter consumption averages 10-25% higher than summer. Causes: cold engine at startup, cabin heating system, frequent urban start-stops, winter tires with higher rolling resistance, denser cold air. On short trips (under 10 km) consumption can be 40-50% higher in the first few minutes.

How do I reduce winter fuel consumption?

Five practical tips: (1) DON'T idle the car to warm up — drive immediately, the engine warms more efficiently under load. (2) Check tire pressure weekly — cold drops pressure 0.1 bar per -10°C. (3) Clear snow from the roof — adds aerodynamic drag. (4) Don't max the heating unnecessarily — alternator load = extra fuel. (5) Combine trips — a warm engine consumes 25% less than a cold one.

Can I use summer diesel in winter?

Technically yes, but at temperatures below -10°C the paraffins in summer diesel begin to crystallize and can clog the filter. All Romanian stations automatically dispense winter diesel from 16 November through 28 February — no action needed if you fuel locally.

Can extra anti-freeze additives damage my engine?

Pump-station winter diesel is already EN 590 compliant — safe for all diesel engines. Aftermarket additives can cause issues if overdosed or uncertified. Recommendation: rely on the pre-additivated winter diesel from the pump rather than extra additives.

Winter fuel in Romania — complete guide

Everything you need to know about winter diesel, cold-weather petrol behavior, increased consumption and how to reduce it. Indicative data updated 2026-06-16.

Winter diesel

In Romania, pump diesel automatically switches between two annual variants per EN 590:

Standard diesel variants in Romania
Variant	Period	CFPP	FAME content
Summer diesel (B10)	1 Mar – 15 Nov	0°C to −10°C	up to 10% biodiesel
Winter diesel (B7)	16 Nov – 28/29 Feb	−20°C	up to 7% biodiesel
Arctic diesel (B7 special)	Mountain regions / extreme cases	−32°C	up to 7% biodiesel

The switchover is managed at the refinery (Petrobrazi, Petromidia) and wholesale depots. From the consumer side, it's invisible — no action needed. By 16 November, all major-network stations already have winter diesel in their tanks.

Petrol in cold weather

Petrol doesn't need a special winter variant — petrol's freezing point is well below any realistic Romanian temperature (-50°C+). The only adaptation: refineries slightly raise petrol's vapor pressure in winter, for faster evaporation needed for cold-engine starting.

This is standardized via EN 228 (RVP — Reid Vapor Pressure). Seasonal variations are automatic and transparent to the consumer.

Why does winter consumption increase?

Summer-to-winter consumption gap averages 10% to 25%, or even 40-50% on short trips (under 10 km). Main causes:

Cold engine: an engine reaches optimal temperature (~90°C) in 10-15 minutes. Before that, the ECU injects a richer mixture (more fuel per cycle) to compensate for reduced evaporation. Short trips never reach optimal temperature.
Cabin heating system: fan, defrosters, heated mirrors, heated seats — all draw from the alternator, which draws from the engine. ~3-7% extra consumption.
Stop frequency: winter traffic (slippery roads, reduced visibility) means more start-stops, each with a consumption spike.
Winter tires: rolling resistance is 5-15% higher than summer tires. ~1-3% consumption impact.
Air density: cold air is denser, so the engine takes in more oxygen per cycle and needs more fuel for stoichiometric combustion. ~2-4% extra.

For a driver averaging 6 L/100 km in summer, winter consumption can reach 7.2–7.5 L/100 km — about 20-30 RON extra per month for typical urban commuting.

How to reduce winter consumption

DON'T idle to warm up — drive immediately. The engine warms faster and more efficiently under load.
Check tire pressure weekly — cold drops pressure 0.1 bar per -10°C. Underinflation = 2-5% extra consumption.
Clear snow and ice from roof, hood, windows. Roof snow adds drag and weight (~10-30 kg).
Use heating moderately. 22-23°C is comfortable; no need for 28°C.
Combine trips. One 30 km drive with warm engine consumes 25-30% less than three 10 km drives starting cold each time.
Check air filter and spark plugs before winter. A dirty filter or worn plugs add 5-10% consumption.
For diesel: check fuel filter before first frost. A near-end-of-life filter can suddenly clog at first paraffin crystallization.
Use Eco mode if available. Recalibrates injection map for economy.

Aftermarket additives — worth it?

Auto stores carry various "anti-freeze diesel additives" — Liqui Moly, Hi-Gear, Wynn's etc. Important clarifications:

Pump-station winter diesel at Petrom, OMV, Rompetrol, MOL, Lukoil, Socar is already additivated per EN 590. No extra additive needed for normal use.
Extra additives become useful only when: (a) you frequently travel to areas with sub-25°C temperatures (northern Norway, Finland, high mountains) or (b) you use diesel stored from summer.
Dosing is critical — overdosing can excessively dilute diesel properties and affect Euro 6 SCR systems. Read instructions carefully.