Oil... how does it work? [split]

You guys might want to read up on what the numbers on the bottle mean

I don’t have it backwards, that’s the point.

Thicker or heavy viscosity oils will take longer to flow through the orifice in the viscometer and end up in higher number ranges such as SAE 50 or SAE 60 for example. If an oil flows through faster being thinner/lighter then it will wind up in a low number range such as SAE 10 or SAE 20 for example.

This allows the engine to get quick oil flow when it is started cold verses dry running until lubricant either warms up sufficiently or is finally forced through the engine oil system. The advantages of a low W viscosity number is obvious. The quicker the oil flows cold, the less dry running. Less dry running means much less engine wear.

The viscosity grade (for example, 5W-30) tells you the oil’s thickness, or viscosity. A thin oil has a lower number and flows more easily, while thick oils have a higher number and are more resistant to flow.

Water has a very low viscosity – it is thin and flows easily. Honey has a very high viscosity – it is thick and gooey.

The viscosity will determine how easily the oil is pumped to the working components, how easily it will pass through the filter, and how quickly it will drain back to the engine. The lower the viscosity the easier all this will happen. That is why cold starts are so critical to an engine because the oil is cold, and so relatively thick.

So my question stands, why it flows easier when warm even though it’s viscosity is higher, which means it’s thicker. :ponder

First number on the bottle is at freezing temp IE “5”, second number on the bottle at operating temp, IE “30”.

Oil is thin at start up so it actually gets flowing through the motor due to paraffin additives in dino oils and natural properties in real synthetics.

http://www.kewengineering.co.uk/Auto_oils/oil_viscosity_explained.htm