What is meant by multigrade? - Millers Oils France

What is meant by multigrade?

Millers Oils France » FAQ » Classic » Classic Engine Oil FAQs » What is meant by multigrade?
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Millers Classic 20W50 Mineral Engine Oil

Millers Classic 20W50 Mineral Engine Oil

Multigrade oils were developed in the 1960’s and have many different formats (20W50, 20W60 etc.).  Prior to this, all oils were monogrades (ie. 30, 40, 50).

This was made possible by the invention of polymers.   Polymers are molecules that expand as they get hotter.  Therefore a multigrade oil can have the viscosity of an SAE20 when it is cold and the viscosity of an SAE50 when hot.  This removes the necessity to change from a thin oil in the winter to a thicker oil in the summer.

The 20w number is the cold viscosity and the 50 number is the viscosity at 100 centigrade.

For details on all of engine oils produced by Millers Oils, please see our full range of Classic Engine Oils, Motorsport Engine Oils and Road Car Engine Oils.

For other useful info please refer to our FAQs page.

Cara Samways
Cara Samways
Gérante – Millers Oils France. Cara est le propriétaire/la gérante de la SARL Adinvenio qui fournit les produits Millers Oils aux particuliers, garages/ateliers, l'équipes de course et les commerces dans toute la France. La famille de Cara a été impliquée dans les voitures classiques et les courses automobiles pendant de nombreuses années. Cara a passé une grande partie de son enfance à Silverstone et sur d'autres pistes de course au Royaume-Uni. Intérêts: les courses automobile, la photographie, la faune et la flore.