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Synthetic oil in 4-cylinder vehicles

Recently my auto mechanic informed me that 100% synthetic motor oil is not recommended for 4-cylinder engines. He informed me that a synthetic blend in the oil best suited for a 4-cylinder. Is this true? I have been using a pure synthetic in my 4-cylinder Toyota Camry. Am I doing any harm to the engine with synthetic oil?


  • edited June 2010
    What type of oil does your owner's manual recommend?

    There is no set rule for all four cylinder engines. It varies by car and engine design.
  • edited June 2010

    Your mechanic's advice is sort of the automotive equivalent of someone telling you that you shouldn't eat celery if you have red hair. Ergo--incorrect, and somewhat bizarre.

    Are you doing any harm to your engine? No
    Are you paying a premium price for something that you likely don't need? Yes

    Unless your part of the country is typically exposed to extremely low temperatures (sub-20 degrees Fahrenheit) in the winter, there is really no advantage to synthetic oil. If you live in more temperate areas of the US, conventional motor oil in the viscosity specified by Toyota is all you need. Also, be sure that you don't exceed 5k miles between oil changes--whether you use conventional or synthetic oil.
  • edited June 2010
    Synthetoc oil is only recommended for 4-bangers when they have turbos. Your Camry does not.

    Turbochargers, because the turbos are spun by the hot exhaust right out of the manifold, at very high speeds, and are lubricated by the oil, expose the oil to much higher temperatures stresses than your Camry engine does. Since synthetic has been shown to better stand up to high temperatures, it's used in turbocharged engines.

    Your engine does not need synthetic. He's being honest in suggesting that synthetc is not "recommended" for 4-bangers (he's no doubt assuming you're talking about your Camry, which is not turbocharged). It's simply not necessary. That's not the same as saying that synthetic would be bad for 4-bangers, only that there's no need to use it.

    There are those who feel that "blended" oils provide better protection for all engines without the added cost of full synthetics. Apparently your mechanic is one.

    I believe he's being honest and saving you unnecessary expense.
  • edited June 2010
    Hogwash, there's no reason why a 4 cylinder can't use synthetic oil. There's no reason why you can't use it in your Camary if you choose to do so. Now you probably won't see any huge benefit in using synthetic oil. But you won't hurt anything. I would look for another mechanic if I were you, next thing you know he'll be wanting to de-coke your valves and revulcanize your tires.
  • edited June 2010
    tsm is right on this one, your mechanic is being straight with you about your car, and saving you money, stay with him and be glad you found an honest businessman to work on your car.
  • edited June 2010
    Here we go, another 40 posts for sure...One Cylinder or sixteen cylinders, it makes no difference..I would not let your "mechanic" work on my lawn mower...
  • edited June 2010
    Here's a new version of the old 'synthetic yes or no' question. This is actually a grammar question. "not recommended" is different than "not required". "not recommended" infers something negative will happen if you use synthetic, which (aside for the extra money you spend) is not true, no harm will come. Had he said "not required" or "not needed" (for Camrys, at least), he'd have gotten an 'A'. As is, he gets a 'C-'.
  • edited June 2010
    harsh texas, harsh.
  • edited June 2010
    Well, if your Camry has one of the sludge prone engines, then he's doubly wrong. If you're a DIY'r ...the cost of some synthetics (many of which are NOT marketed as extended drain oils - in fact, VERY FEW ARE) is not too far above conventional and is easily justified in a (perhaps) situation like yours.

    Otherwise, a synthetic will not extend the life of your engine. It will probably last longer itself under more stressful conditions than a conventional. It will take more heat, it will flow slightly easier when cold. It will endure oxidation better/longer.
  • edited June 2010
    The sludge-o-matic was a V6.
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