Switching From Synthetic back to Conventional Oil

Synthetic oils will provide better protection than conventional oils, and especially in colder climates, but contrary to public opinion, switching back and forth between full synthetic and conventional oil will not damage the engine. Of course, this depends on the current engine condition and the quality of the conventional oil being used.  But switching between synthetic and conventional oil will not cause problems - because the oils are compatible, you can switch back and forth as often as you like.

How Synthetic Oil is Made

Synthetic engine oil products are produced through a synthesis process that takes very small molecules and assembles them into larger designer molecules with premium lubricating properties. Others may be produced through a synthesis process that takes very large molecules, breaks them apart, and re-arranges them to produce designer molecules with premium lubricating properties. In either case, the end products are base fluids with extremely good lubricating properties.

How Conventional Oil is Made

Conventional base stocks are refined from crude oil through various hydrorefined/hydrotreated refining processes to separate and/or convert undesirable compounds to yield a suitable finished base stock.  

Synthetic Oil is NOT Fake Oil

Synthetic oils are not fake - they are still derived from crude. However, synthetic engine oils use higher base stocks than conventional oils and go through a synthesis process in which all the molecules are made into the same size for a higher film strength.

Full synthetic motor oils also contain man-made additives that are added to the oil to increase film strength, the ability to handle high temperatures, etc. Synthetic or synthetic blended oils are not intended to extend oil change intervals. These oils are recommended for use in harder working engines and to assist with gas mileage, not to extend service intervals beyond what the manufacturer recommends.