My garage
Categories
- Viscosity
Buy 0W-8 engine oil
0W-8 is the thinnest grade there is for production engines. It exists for a handful of Japanese hybrid engines developed for it - and for nothing else. Without the grade in the handbook, this oil does not belong in your engine.
Why this grade exists
Fuel consumption. One more step below 0W-16 saves a little more pumping work, and in a hybrid drivetrain that restarts the combustion engine constantly and often runs it cold, that share is measurable. To keep the thin film load-bearing at all, the engine is built around it: bearing clearances, oil pressure, oil pump, additive package - it all belongs together.
No substitute for thicker grades
That is the one rule you need to know about 0W-8: it is not the "most modern" and therefore best variant, but a special design. In an engine that calls for 0W-16, 0W-20 or more, the lubricant film at operating temperature is thinner than intended - particularly at full load, with a trailer and at high oil temperatures.
The reverse case is less critical: if your vehicle calls for 0W-8, you may use a 0W-16 to top up in an emergency. At the next change the specified grade goes back in.
What to check before you buy
Does the owner's manual or the oil filler cap say "0W-8"? On Japanese imports it is worth looking at the original handbook, because European documents often do not list these grades. And reckon with a small fill quantity - usually well under 4 litres, so buying one bottle more than you need is not a big item.
If you are unsure, select your vehicle in the oil finder: the matching there runs on the manufacturer specification for your specific engine.
Frequently asked questions
Is 0W-8 better than 0W-20?
No, it is laid out differently. For an engine specified for 0W-20, 0W-8 is too thin; for one that calls for 0W-8, 0W-20 is too thick and costs the consumption advantage. There is no better oil here, only a matching one.
Which vehicles run 0W-8?
Individual Japanese hybrid engines developed for it. The grade is not widespread in Europe, and without an explicit figure in the handbook you should not use it.
Can I top up with 0W-16 in an emergency?
Yes, that is the defensible stopgap - considerably better than carrying on with too low an oil level. At the next change 0W-8 goes back in, provided your manufacturer specifies it.
