Everything about SAE viscosity
Everything a car owner needs to know
On closer inspection, engine oil viscosity is one of the least obvious parameters, and it often becomes a stumbling block when choosing an oil. The trouble is that there are countless different points of view — from sellers, official service technicians, “garage” mechanics and simply experienced car owners. And these opinions often contradict one another.
In reality, if you understand at least in general terms what oil does inside an engine, the question of viscosity shouldn’t be overly complicated.
- What is oil viscosity? What it's for Why engine oil needs viscosity: why the oil in an engine heats up to 140–150 °C, how the engine maker picks compromise parameters and what SAE describes.
- How to decode the viscosity index Decoding the SAE marking using 5W-30: what the number before the W means for cold starts, what the second number shows and where 0W-16 and 0W-8 come from.
- Which viscosity is better for the engine? Why a higher high-temperature viscosity does not make an ordinary engine better: a magazine’s test of grade 50 oil in a VAZ “eight” instead of the specified 40.
- Popular misconceptions about viscosity Three myths about engine oil viscosity: a “sporty” oil for fast driving, modern thick oils for old engines, and going above the viscosity the carmaker approves.
- Viscosity value table The SAE J300 table of engine oil grades from 0W to 60: limiting viscosities in the cold, at 100 and 150 °C, plus an update on the new grades SAE 16, 12 and 8.
- What is oil viscosity? Myths and truth Which oil is better, 0W-30 or 5W-50: the one the engine was designed for. An introduction to the section on myths about engine oil viscosity codes.
- Once again about oil viscosity What happens to the oil on a cold start, in town, on the motorway and in the heat, what HTHS is, and why a dealer may advise a different viscosity.