Synthetic oil questions

When I taught an Engines class in St Paul, MN a couple of years ago, we performed a very non scientific experiment that really opened my eyes. It was the middle of winter, and I sent my students to the parts store to buy different wieghts and brands of oil, (0W-20, 5W-20, 10W-30, 10W-40, 30) Quaker State, Pennzoil etc.
I also had them buy 1 qt of Mobil 1 10-30. We put the oil (still in the bottles) outside in aprox minus 10 degree F. overnight. In the morning, we opened and and poured the oils just to see how fast the bottles would empty. Shall we say an exerscise in "cold viscocity!" The lower grade oils (0W-20, 5W-20) all poured, but slowly. The 10W poured a little slower, but still they flowed. The 30 oil just glubbed, we laughed at how long it took. But the amazing thing was the Mobil 1. It poured like it was room temperature.

So, because more damage could occur on cold starts, I recommend synthetic oils. I have no way of testing high temperature viscocity, but due to the nature of the beast, I believe synthetics are superior (ie race cars and fleets).
Some synthetics also claim longer drain intervals, but I caution about that.
I also don't believe in oil addatives- if you use an oil that is rated according to your OE (Toyota) and change according to maintanance schedule, many happy motoring miles should result.

http://www.amsoil.com is a premium synthetic mfr, and has good web site.

 

http://www.amsoil.com is a premium synthetic mfr, and has good web site.
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I use Amsoil (oil and filters) according to their drain schedule. Traded-in a 2001 Nissan Frontier with 110,000 miles this year with no issues. My daily driver is a 2000 Honda Insight with 160,000 miles. It still does not use any oil between changes.

 

<div class='quotetop'>QUOTE(lagreca @ Oct 27 2007, 01:14 AM) [snapback]531107[/snapback]</div>

All of your questions have been debated at length before on PC. Try searching on synthetic oil.

The Cliff Notes response to your questions are that there are a number of brands of pure synthetic oil on the market. Pure synthetic costs more than a synthetic blend. If you are going to stay with the 5,000 mile change interval, my personal opinion is that a synthetic blend will do fine. Filters are a similar topic as synthetic oil (many opinions on the subject). The OEM filter is fine for the 5,000 mile change interval. If you want "more" filtration, you can get as much as you are willing to pay for.

 

<div class='quotetop'>QUOTE(lagreca @ Oct 27 2007, 04:14 AM) [snapback]531107[/snapback]</div>

Synthetic Oil for automotive applications was first invented and sold by Amsoil. Today Amsoil and Mobil 1 are the best in 100% synthetic because they are made, not from petroleum like pennzoil and the other brands, but from mineral oil and they have the high polyalphaolefin (PAO) content that qualifies them as true synthetic oils. Synthetic blends are a waste of money because you reproduce all the reasons you avoid petroleum oil in the first place by blending synthetic with the regular petroleum oils.

I have 5500 miles on my 2007 Prius Touring Edition, I just changed the oil for the 4 th time, the last two were 100% synthetic (Amsoil and Mobil 1). New engines produce many more wear particles in the first 5000 miles than they do in the next 50,000 miles, and filters do not remove wear particles below 10 microns. If you want to remove them, change the oil. Hence I changed the oil at 500 miles, 1500 miles, 2500 miles and 5500 miles. Best fiilters are Amsoil, Mobil 1, and Hastings ! They cost more, you get what you pay for. Since a Prius only holds 4 quarts of oil it is small insurance to change and use 100% synthetics.