Dino Vs Synthetic
Dino oil is a refined crude. Refining isn't a perfect process, so there will still be impurities in the finished product.
Dino oil contains paraffin, which over-thickens the oil when cold, in turn greatly increasing the load on your starter and eating fuel economy.
Any refined oil is made up of molecules that vary in size. Smaller molecules evaporate more readily, leaving larger molecules behind and causing the oil to get thicker with age.
These varying molecules also limit the friction-reducing ability of the oil.
On the other side of the coin, here's why we prefer synthetics:
Being a manufactured product, synthetic engine oil molecules are very uniform in size, meaning evaporation has minimal impact on viscosity.
Synthetic oil molecules are also rounder in shape than refined oil molecules, giving them superior lubrication characteristics.
Synthetic oils maintain a more constant viscosity over a wider temperature range, meaning it's safer to tag high RPM on a cold engine because a synthetic oil film is less likely to break down. (Analogous to tearing a piece of cold clay.)
A lubricant that's very slippery reduces frictional power loss and improves fuel economy.
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