It is genetic - in my family there is no history of it as it is a recessive gene but my mum and dad were both carriers. In Scotland up to 13% of the population has red hair, but around 40% of the population is thought to carry the recessive gene responsible for the world's rarest natural hair colour.
On the other hand, synthetic base oil molecules are chemically controlled, which provides increased ï¬ lm strength and lubricity over petroleum oils. The performance qualities of base oils have a marked impact on the performance qualities of the ï¬ nished product.
What is the oil change interval for synthetic oils vs regular oils? You can run a conventional oil 5K miles but you should be able to run a synthetic oil 7500 to 10000 miles (synthetic oil change intervals are longer) A tip on how often change synthetic oil?