I don't see why not, Isn't the synthetic blends ( like Ford's Motorcraft oil ) just a synthetic and conventional mix?

 

I have a new Volvo inboard and in my engine owners manual it clearly says if you switch to synthetic oil DO NOT switch back to conventional oil. I'm not sure if they are correct that its not a good thing to do but I figure they know what they are talking about. This could have been policy before the newer generations of synthetics I don't know.

 

I am on my second oil change using Valvoline Synthetic 5w20 and withing a few days of the first syn change I noticed improved power....my wife has noticed better mileage as she is the one who fills it. We are using sythetic with midgrade gas and it is like a new truck. It's an 09 with 25,000 kms, Went since September 2011 and the oil was still fairly clean, not that many kms...less than 8000 so only 5000 miles. I am very happy with it get it on sale for 30 bucks with a filter, I have to buy 2 and I have 3 quarts left over and a filter which my sons car takes the same one. We got K&N filters this time so we shall see any differences, last time was Fram TG

 

I don't know anything!! I have been reading truck forums for several years now, Dodge, Chevy, and Ford, reading about synthetic oils, but this is the first time I have ever heard about this Class I, II, (is that what it is?) stuff. All I know is that I use full synthetic in all my vehicles and usually buy Mobil 1, Castrol, but cannot find Valvoline synthetic any more. I usually buy on price and switch between brands (except Wal Mart's brand). But, I have read on other forums that Mobil 1 is not as good, now here I am reading that Mobil 1 an Amsoil are the better classes?? Oh me, I am lost, lost I tell ye...

 

I found that synthetic oil gives birth to the "hemi tick"
I'm staying away!

 

Now HERE is the difference between what we commonly call "Synthetic" and "True Synthetic". It all has to do with what they start with to make the product and what the API (American Petroleum Institute) allows to be called "Synthetic".
Some synthetic oils are made from TYPE III base stocks. Type III is conventional oil. To make it into a synthetic it's synthesized in the presence of hydrogen under very high pressure to produce a lubricant (while mineral based) that has more uniform molecules and better lubricating properties than standard conventional oil. The API allows this to be marketed as "Synthetic" oil in the United States. In many countries such as Germany and Japan, a lubricant that starts with a Type III base CANNOT be marketed as a Synthetic.

A second method is commonly used whereby the base product is a Type IV lubricant (polyolefin) which while still an organic compound is not a petroleum product (oil). The API commonly classify organic compounds that are not petroleum based as PAOs. Because polyolefin is organic and not man made, lubricants produced from it are not "100% synthetic" but because it's not petroleum it can be marketed as a Synthetic Lubricant in those countries who DO NOT allow oils that begin as conventional petroleum to be marketed as such.

The third is a TRUE or 100% SYNTHETIC Lubricant, whereas the base material is not petroleum or organic (PAO) and instead is a 100% man made product. These bases are generally diesters, polyolesters or benzenes.

I'm not going to get brand specific here, but MANY oils marketed IN THE UNITED STATES as "Synthetic" not only start with a petroleum (conventional oil) base but in many cases contains up to 69% plain old conventional oil. As long as there is 31% synthetic oil (which can also be made from conventional oil) then it can be called "Synthetic". If it has less than 30% synthetic then it must be called a "BLEND".

While I don't think there is enough difference between a synthetic oil that is based on Group III, IV or V bases to make much of a difference, I have a HUGE problem with companies being able to market a product that is mostly conventional oil as a synthetic oil. That's our government protecting us again...

 

I found my "tick" was loudest when using Mobil 1, now I used Mobil 1 for close to 20 years and NEVER had an oil related issue. I've since tried Royal Purple, Castrol Edge and Valvoline SynPower. I've found the tick to quietest (almost undetectable) with RP and Valvoline and the Castrol product was a good bit quieter than the Mobil 1, but not as quiet as the other two.

I really don't have an issue with conventional oil, unless the manufacturer specs a synthetic (most high end, performance engine makers do) although I haven't used a conventional since the early '90s in anything. Just remember that as a rule conventional oil breaks down faster, floats less contaminants and will produce more deposits (sludge) as it losses it's properties in the engine. So I'd do more frequent changes with conventional than if running a synthetic product...

 

Good explanation, Hammer, but to clarify ---- all this stuff is still derived from petroleum/natural gases..... it's not magic, just engineered lubricants, engineered to such higher standards and specifications, that they really are better lubricants. It's all part of the refinning process, to get the best base stocks to start with. Time consuming, and expensive. I hope this helps. " From Ency Britannica, and many other sites. "

"polyolefin, any of a class of synthetic resins prepared by the polymerization of olefins. Olefins are hydrocarbons (compounds containing hydrogen [H] and carbon [C]) whose molecules contain a pair of carbon atoms linked together by a double bond. They are most often derived from natural gas or from low-molecular-weight constituents of petroleum, and their most prominent members are ethylene and propylene. These two compounds are “lower olefins”—that is, olefins whose molecules contain only one pair of carbon atoms. “Higher olefins,” containing two or more pairs of carbon atoms per molecule, include butene (butylene) and methylpentene. All of these olefins are made into polymers, but by far the most important are polyethylene and polypropylene. The wide array of uses to which these versatile plastics can be applied and the huge quantities in which they are made so overshadow the other olefin polymers that the term polyolefin is frequently understood to refer only to them"