What does viscosity cst mean

As the old saying goes, "it's as slow as molasses going up hill on a cold day. So whereas a high viscosity engine oil may be good for boundary lubrication, they can be a real challenge to move when the weather is cold. What this means is that an engine may be slow to get lubricanted if the viscosity is too high and the temperature too low.

For the car or truck owner this means when they go out to start their vehicle on a cold day, a thinner oil will flow more freely and lubricate more efficiently than a thicker oil. The Society of Automotive Engineers established clear standards that define the viscosity grade of an engine oil. Unlike other "softer" parameters, lubricants either meet, or don't meet these standards. As shown in the graph below, the average viscosity for the 5W major brands tested is All are skewed to the lower end of the acceptable API range.

These oils can be used regardless of season. Monograde oils are still used for special purposes but usually not as engine lubricants. There is no single best motor oil viscosity.

Older cars are usually ok with a 10W oil, while newer cars usually like a lower viscosity oil, like 5W, 0W or sometimes even 0W API SN or GM Dexos 2 required by the car manufacturer then the oil should meet those specifications and should also have the correct viscosity in order to be used for that particular vehicle.

Viscosity actual viscosity, not the viscosity grade changes with temperature. When the film thickness is low, the engine may experience more metal to metal contact and higher levels of wear. When it is too thick, it may not flow fast enough or to some parts of the engine also leading to higher levels of wear and less efficient engine operation.

In simplest terms, viscosity is a measure that speaks to a liquid's resistance to flow. Fluids with a high viscosity are thick and flow slowly. In particular bearings, the camshaft, the piston rings and liner.

Because of the extreme heat around the crankshaft, the oil viscosity for HTHS viscosity is measured at c. They created special low viscosity oil that slips through the bearings easily and offers a fuel economy benefit — whilst still protecting against wear.

You can see that the 0W oils must be at least 2. All in the spirit of maximising fuel economy. A point to note is that these oils are designed for specific fuel economy engines. The 60 grade on the SAE J table has a with a whopping Compare this to the new kid on the block, a 0W-8 weighing in at between 4 and 6.

The table below neatly brings together these four concepts. Modern oils at high temperatures are inching their way to the viscosity of water! They are there to help you. Workshop managers stay tight-lipped about staff over fears they could be recruited by rivals.

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Old specs to be discontinued as new oil sequence is introduced. Our CAT Editor reports the latest. Your email address will not be published. Save my name, email, and website in this browser for the next time I comment.

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