The Germans in WWII developed synthetic oil because their tanks and trucks wouldn't start in the 20 below zero on the Russian front.  Synthetic Oil handles extreme heat and cold where conventional oil fails.

Most mechanics, engineers and even oil industry "experts" don't have a good understanding about sythetic oil. The oil companies want you to continue wasting oil and fuel making their profits go up.

I've used AMSOIL 100% Synthetic Oil since 1995 and my testimonial is, I get about 20% more MPG and I change oil and AMSOIL's nano Fiber Filter, once a year or every 25,000 miles whichever comes first.  I save 40 quarts of oil and 8 conventional oil filters, or about 90% a year on oil/filters.  I reduce my oil usage by 80%

We recently bought a 2007 Toyota Camry XLE 4 cyl and drove from Missouri to California with conventional oil in the engine. We consistently got 30 mpg and 32 mpg with the AC on full blast. 

Before we came back to Missouri we changed over to AMSOIL 100% synthetic oil.  We got 38 and 40 MPG on the way back, a 2,200 mile trip.  We got a 6.4 mpg increase with the AC running full blast all the time.  So I save my time changing oil and nano fiber filter once a year, I save money reducing the amount of oil/filters I use and I save gas.

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