This is completely an urban legend. Not such thing happens!!! It was a myth perpetrated by the petroleum based oil manufacturers many years ago, and the legend seems to never seem to die.

The truth is, synthetic & petroleum oils are 100% compatible! 8)

 

In an effort to set the record straight, I have assembled here ten of the more persistent myths about synthetic motor oils to see how they stack up against the facts.

Myth #1: Synthetic motor oils damage seals.

Untrue. It would be foolhardy for lubricant manufacturers to build a product that is incompatible with seals. The composition of seals presents problems that both petroleum oils and synthetics must overcome. Made from elastomers, seals are inherently difficult to standardize.

Ultimately it is the additive mix in oil that counts. Additives to control seal swell, shrinkage and hardening are required, whether it be a synthetic or petroleum product that is being produced.

Myth #2: Synthetics are too thin to stay in the engine.

Untrue. In order for a lubricant to be classified in any SAE grade (10W-30, 10W-40, etc.) it has to meet certain guidelines with regard to viscosity ("thickness").

For example, it makes no difference whether it's 10W-40 petroleum or 10W-40 synthetic, at -25 degrees centigrade (-13F) and 100 degrees centigrade (212 degrees F) the oil has to maintain a standardized viscosity or it can't be rated a 10W-40.

Myth #3: Synthetics cause cars to use more oil.

Untrue. Synthetic motor oils are intended for use in mechanically sound engines, that is, engines that don't leak. In such engines, oil consumption will actually be reduced. First, because of the lower volatility of synlubes. Second, because of the better sealing characteristics between piston rings and cylinder walls. And finally, because of the superior oxidation stability (i.e. resistance of synthetics against reacting with oxygen at high temperatures.)

Myth #4: Synthetic lubricants are not compatible with petroleum.

Untrue. The synthesized hydrocarbons, polyalphaolefins, diesters and other materials that form the base stocks of high-quality name brand synthetics are fully compatible with petroleum oils. In the old days, some companies used untested ingredients that were not compatible, causing quality synlubes to suffer a bum rap. Fortunately, those days are long gone.

Compatibility is something to keep in mind, however, whether using petroleum oils or synthetics. It is usually best to use the same oil for topping off that you have been running in the engine. That is, it is preferable to not mix your oils, even if it is Valvoline or Quaker State you are using. The reason is this: the functions of additives blended for specific characteristics can be offset when oils with different additive packages are put together. For optimal performance, it is better to use the same oil throughout.

Myth #5: Synthetic lubricants are not readily available.

Untrue. This may have been the case two decades ago when AMSOIL and Mobil 1 were the only real choices, but today nearly every major oil company has added a synthetic product to their lines. This in itself is a testament to the value synthetics offer.

Myth #6: Synthetic lubricants produce sludge.

Untrue. In point of fact, synthetic motor oils are more sludge resistant than their petroleum counterparts, resisting the effects of high temperature and oxidation. In the presence of high temperatures, two things happen. First, an oil's lighter ingredients boil off, making the oil thicker. Second, many of the complex chemicals found naturally in petroleum basestocks begin to react with each other, forming sludges, gums and varnishes. One result is a loss of fluidity at low temperatures, slowing the timely flow of oil to the engine for vital component protection. Further negative effects of thickened oil include the restriction of oil flow into critical areas, greater wear and loss of fuel economy.

Because of their higher flash points, and their ability to withstand evaporation loss and oxidation, synthetics are much more resistant to sludge development.

Two other causes of sludge -- ingested dirt and water dilution -- can be a problem in any kind of oil, whether petroleum or synthetic. These are problems with the air filtration system and the cooling system respectively, not the oil.

Myth #7: Synthetics can't be used with catalytic converters or oxygen sensors.

Untrue. There is no difference between synthetic and petroleum oils in regards to these components. Both synthetic and petroleum motor oils are similar compounds and neither is damaging to catalytic converters or oxygen sensors.

Myth#8: Synthetics void warranties.

Untrue. No major manufacturer of automobiles specifically bans the use of synthetic lubricants. In point of fact, increasing numbers of high performance cars are arriving on showroom floors with synthetic motor oils as factory fill.

New vehicle warranties are based upon the use of oils meeting specific API Service Classifications (for example, SG/CE). Synthetic lubricants which meet current API Service requirements are perfectly suited for use in any vehicle without affecting the validity of the new car warranty. In point of fact, in the twenty-five years that AMSOIL Synthetic Lubricants have been used in extended service situations, over billions of miles of actual driving, these oils have not been faulted once for voiding an automaker's warranty.

Myth #9: Synthetics last forever.

Untrue. Although some experts feel that synthetic basestocks themselves can be used forever, it is well known that eventually the additives will falter and cause the oil to require changing. Moisture, fuel dilution and acids (the by-products of combustion) tend to use up additives in an oil, allowing degradation to occur.

However, by "topping off", additives can be replenished. Through good filtration and periodic oil analysis, synthetic engine oils protect an engine for lengths of time far beyond the capability of non-synthetics.

Myth #10: Synthetics are too expensive.

Untrue. Tests and experience have proven that synthetics can greatly extend drain intervals, provide better fuel economy, reduce engine wear and enable vehicles to operate with greater reliability. All these elements combine to make synthetic engine oils more economical than conventional non-synthetics.

In Europe, synthetics have enjoyed increasing acceptance as car buyers look first to performance and long term value rather than initial price. As more sophisticated technology places greater demands on today's motor oils, we will no doubt see an increasing re-evaluation of oil buying habits in this country as well.

CONCLUSIONS
Since their inception, manufacturers of synthetic motor oils have sought to educate the public about the facts regarding synthetics, and the need for consumers to make their lubrication purchasing decisions based on quality rather than price. As was the case with microwave ovens or electric lights, a highly technological improvement must often overcome a fair amount of public skepticism and consumer inertia before it is embraced by the general population.

But the word is getting out as a growing number of motorists worldwide experience the benefits of synthetic lubrication. The wave of the future, in auto lubes, is well under way.

 

Get a load of this one! >>> http://www.motoroilbible.com/ebook.html

 

Yea I have seen this e-book, it is really good! After reading the ad, I sprang for it. Once you buy it, the author - Michael Kaufman will send you the .pdf file of the book so you can copy and print it! tlk

 

I use Amsoil from bumper to bumper. Synthetics save you time and money

 

Each to his own... :roll: :wink:

 

Mercy! :shock: I know someone changing their SAE 15W-40 Synthetic www.amsoil.com/storefront/ame.aspx every 60,000 miles only if needed after testing. He uses a killer Harvard filter. www.harvardcorp.com
One could also use the Spinner II www.spinnerii.com and get the same if not better results.

 

I forgot to add. You might like this for dusty areas to help save on air filter costs.

http://www.gwdiesel.com/turbo.htm

 

I use synthetics in the tranny and the diffs, and dinosaurs in the engine.

I end up changing the oil in the engine before I add it.

I get the engine oil analyzed once a year.

This is all done in the shop and usually when I get the Commercial Vehicle Inspection.

Students grease the the truck, wash the truck, clean the windows, chain the truck in the winter.

I drink coffee and say "Right" & "left" & "that was a bad choice"...and if need be.....STOP!!!!!!

Tough job, but someone gots to do it.

The hardest part of my job is when you see grown men cry.

 

have i missed the reason why you can't change to synthetic in an older engine? i have a hard time understanding that changing will cause leaks if you don't have leaks now, but i don't want to take the chance without hearing from someone that has done it or if one of these salesman can tell us their product won't cause a leak in engines that has used petroleum products previously.