We get this question a lot. There is a perception that 'synthetic' always means better. We advise customers that there are applications where synthetics out-perform and out-last conventionals and really are the best and most cost-effective recommendation but there are also applications where it does not make sense to spend the extra money for a synthetic. The majority of synthetic oils we deal with are formulated with polyalphaolefin (or PAO for short) base oils. PAO's start life as conventional crude oil but by special refining and manufacturing processes are changed into base oils with molecules that are of uniform size and shape where as conventional base oils are comprised of molecules of great variety in size and shape. This uniformity makes the oil perform very predicitably at high and low temperatures and because the molecules are uniform, they stand shoulder to shoulder so tightly that oxygen molecules cannot easily attach and cause oxidation. Oxidation is one of the main reasons an oil 'wears out' and has to be changed. A consequence of this molecular consistancy is that because the synthetic base oil molecules form this inter-locked 'wall' (think of the Spartans with their shields in the movie 300) not only do they resist the attachement of oxygen (the enemy) but they can also can resist accepting additives (the good guys). Early synthetics were formulated with conventional addtives and solvency was an issue. After much research and development, a new generation of additives have been developed which synergize well with the synthetic base oils.

Synthetics really shine in gear cases which are typically sealed from dirt and water and not subjected to the contamination of combustion by-products, fuel and coolant that are present in an engine. However synthetic gear oils can become contaminated with wear metals from gears and bearings. Synthetic gear oils offer superior high and low temperature performance, extended life which is good for gear boxes that may not be easily accessed for service, and potential energy savings because of reduced fricition and easier pumpability within the system. Modern trucks uniformly use synthetic transmission and final drive oils. As horse-power and loads have increased at the same time as reduced oil capacity and increased use of fairings for streamlining which reduces air flow under the truck, trannys and final drives would cook and die under the stress without sythetics oils keeping them cool and lubricated.

So what about synthetic engine oils? My first question is "what problem are you trying to overcome by using a synthetic engine oil?" Sometimes, it boils down to "if it ain't broke, don't fix it" meaning if you are doing well with a conventional engine oil, why spend more for a synthetic? One good reason to use a synthetic engine oil is cold weather starting. Synthetic engine oils crank easier and engines start easier and have oil circulating sooner thus preventing the wear that occurs in a cold dry start. Because of their capacity to reduce friction, synthetic engine oils may also offer increased fuel mileage. Synthetic engine oil may also be justified in engines in heavy duty service in hot weather. A synthetic engine oil resists viscosity degradation and stays in grade better at high temperatures.

How about for extending drain intervals??? My opinion is that using a synthetic engine oil to extend the drain interval is not a good idea. The conditions in an engine are faced by the oil are the same whether it is a synthetic or a conventional formulation. The combustion process produces soot, which along with unburned fuel, traces of coolant and wear metals which all end up in the oil. This needs to come out regularily before the oil is over-burdered with these contaminents and its lubricating qualities compromised. Unless you have a cold or hot issue- I generally recommend that you buy a good conventional engine oil and change it regularily and get rid of all those nasty contaminents before they cause damage. For what you would typically spend on a synthetic oil change, you could do two oil changes with a good conventional and have a cleaner engine. Exceptions- you have a new GM that requires dexos 1 qualified oils which are synthetics OR you have a 'toy' or 'investment' that you don't mind spending the extra bucks for and get peace of mind believing that you are using only the best in your baby. That's fine. I run SynGard Full Synthetic 5W-30 in my wife's Lexus- not to extend the drain but because I want that sucker to last for ever and if spending the extra bucks for the full synthetic might help it hold up better or if we happen to screw up and not get the oil changed on time, I'd rather in that case that it be on the full synthetic than a conventional. It's insurance and peace of mind. Call or come see me and we will fix you up with a synthetic but please don't buy a synthetic and try and run it forever. Even if that synthetic is the 'best' you still need to get the junk out of your engine regularily. The good news is that if you decide you want a full synthetic, at Doolittle oil our SynGard line offers some very good full synthetic engine oils at very good prices. If you need or just want a full synthetic engine oil come on down!

FYI- our XP PCMO's are synthetic blend products. You get some of the benefits of a synthetic but at conventional oil price.

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