Cold starting is the most damaging moment in an engine's life. Estimates suggest that between 60 and 80% of all engine wear occurs in the first few seconds after a cold start at low temperatures. Choosing a winter oil is therefore not a marketing exercise but a genuine engineering task.
Decoding the grade
In an oil designation such as 5W-30, the figure before the W indicates the winter viscosity grade (W for winter). The lower the number, the more easily the oil flows at low temperatures.
Approximate cold-start ranges:
- 0W — down to −35°C
- 5W — down to −30°C
- 10W — down to −25°C
- 15W — down to −20°C
- 20W — down to −15°C
The figure after the W (30, 40, 50) is the viscosity at an operating temperature of +100°C. The higher it is, the thicker the oil when hot.
What to choose for which conditions
- Moscow, St Petersburg, Uzbekistan (lowlands): 5W-30 / 5W-40
- Northern Russia, Kazakhstan, Siberia: 0W-30 / 0W-40
- Warm regions (the south, the Caucasus): 10W-40
- Garage-kept all year round: 5W-X is sufficient
What else to look at
- The vehicle manufacturer's approval (for example MB 229.5, VW 504 00) — always check against the owner's manual
- The ACEA class (C3 for diesels with a DPF, A5/B5 for petrol engines)
- The oil type — a synthetic always copes with frost better than a mineral oil
Practical advice
- Do not put a cold engine under load straight away — give the oil 30-60 seconds to reach every assembly
- Change the oil slightly more often if you drive short distances (the oil never fully warms up and accumulates moisture)
- Do not economise on oil in winter — a small difference in price makes a large difference to service life
In the Krüger catalogue you will find a range of winter oils carrying approvals from the world's leading vehicle manufacturers.
