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synthetic oil reviews

I am trying to find a independant review of synthetic oil. No Amsoil commercials please!!!
<br/> I want to switch my Scion XB over to a Full synthetic.


  • edited May 2010
    Just about any brand name synthetic that has API ratings will give you all the benefits of switching from non synth . No miracles there though .
  • edited May 2010
    Yep, no need for a review, they're pretty interchangeable. If you want to do this, Mobil1 is typically available for a good price by the jug at Walmart. Why do you want to change?
  • edited May 2010
    I want to extend my oil change intervals
  • edited May 2010
    I wouldn't do that, even with synthetic oil.
  • edited May 2010
    > I want to extend my oil change intervals

    What year is your Scion XB, and is it still under warranty? If so, ask the dealer if they will still honor the warranty if you go beyond the oil change schedule documented in your owner's manual.

  • edited May 2010
    I want to extend my oil change intervals

    I feel it's OK to extend oil change intervals using synthetic oils. There's really no reason to use them unless you can. Regular oils are good and cheap enough for normal change intervals. But, if you use a car in high mileage situation, where combustion by products are not likely to accumulate as much and you do it to compensate for oil break down, then yes. If you're an average miler of 15k to 20k per year but do mostly highway, yes. Stop and goer with frequent engine shut offs like many people do with fewer than average miles per year, than no.

    Under ideal, high mileage, heavy highway use, 7500 to 10K mileage intervals are used regularly, and successfully by many agencies. We guys who drool over used police CV as used cars understand the less frequent but successful (10K around here), oil change intervals they have. Your tax dollar and pocket book would want it no other way. I know retired cops who do it now with their own vehicles. They're converts.

    It's foolish and a waste of good money, to use synthetics and change oil too frequently (as with any oil type), except in very specific high load circumstances, or very cold weather applications. Frequent oil changes (3K or less) are often way over rated.

    Bottom line; how you use your car will help determine whether it's a good idea.
  • My own perspective on using synthetic to extend oil change intervals is that doing so is not a good idea. While I respect that synthetics survive extreme heat better, such as that caused by turbochargers, synthetics are just as susceptable to particulate contamination and to dilution and contamination from combustion blowby as dino oils are. All engines have minute amounts of blowby, even new ones.

    In short, synthetics are subjected to contamination just as dino oils are. If your owner's manual recommends synthetics, then by all means use them. But if it does not, I remain unconvinced that under normal operating conditions it's superior.

    I also remain unconvinced that it should be used to extend oil change intervals. One of the oil's many tasks is to wash down the cylinder walls, leaving a residue to lube the cylinders after the oil rings wipe them down. I believe that washes with oil carrying 5,000 miles worth of contamination are still better than washes with oil carrying 10,000 miles worth of contamination.

    And now, my disclaimer. I have no data to back me up. I've yet to find any comprehensive studies that look at the long term effects of synthetic with extended oil change intervals versus dino oil with manufacturer-recommended oil change intervals. If any such study exists, I'd truely be interested in seeing it. Everything I've ever seen only compares performance of dino against sythetic in controlled lab experiments that may or may not represent real world use. And the lab experiments were all done in the name of selling synthetic.
  • edited May 2010
    The math is really against you. Synthetics cost 3-4 times the price of normal dino oil and the most you would be able to safely extend the drain interval is 25-50%!!!!!! If your car is under warranty, you cannot extend the interval at all without voiding it.

    This is the 21st or so post on that specific subject, I believe, and the best way to get maximum engine life at the LOWEST OVERALL COST is:

    1. Use normal oil recommended for the engine.

    2. Change oil and filter at the recommended interval for highway driving in normal weather.

    3. For stop and go, and severe operation, drain oil every 3000-5000 miles.

    If you do the above, your cost will be less than 1/2 of using synthetic and the engine will outlast the rest of the car!!!

    P.S. This is all the review you need!
  • edited May 2010
    THIS is where you go to obsess about Motor Oil..
  • edited May 2010
    If you shop at walmart they'll cost you about 30-40% more, not 3-4 times as much. If it costs you that much you're being ripped off. Walmart carries a lot of synthetics in 5 quarts jugs for a little over $20, their prices for the same size jugs of conventional are about $12-14
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