Since there has been some mention and interest about synthetic oils, I thought it might be nice to have a post on that specific topic.

The Honda Insight forums, here and insightcentral.net, have a wealth of experience in mileage-related issues. The same may be true for Prius forums, but since my history is Insight-derived, that will be my starting point for this discussion.

Many Insight owners believe, based on trial-and-error, that using synthetic oils (such as Mobil 1) is not simply good for engine life, but also for adding 1-2 MPG in mileage / fuel economy.

Is there other data that would support claims of mileage improvement? When any of us TCH users makes a switch to synthetic, PLEASE do your best to reliably document before-and-after mileage changes.

 

I believe a 1 to 2 mpg improvement in a vehicle that's getting 50 to 60 mpg would be hard to pinpoint to any specific change in environment unless you were doing a very controlled test. Over a 150 mile test the difference in 55 mpg and 57 mpg would be less than 1/10 of a gallon of gas.

I don't have a problem with anyone spending all the want on their cars. I do worry though that less experienced people are made to be afraid (by dealers or fanatics) that they are not taking care of their engines, thus they buy into a lot of unnecessary maintenance.

Other than financially there is no problem that I am aware of by over maintaining your vehicle. That's a matter of choice, not necessity.

 

I switched to mobil 1 0w20 at my second oil change right around the time the regular unleaded fuel changed to a 10% ethanol reformulation here in Taxachusetts. Haven't noticed any difference in FE/mpg. Maybe the synthetic oil offset the change from MTBE to ethanol difference but I don't have any data to prove it. I am still getting about 50-52 mpg now that summer is here.

 

Check out AMSOIL. It is the "original" synthetic oil. AMSOIL has been around since the early '70s, before Mobil 1 and is based on synthetic base stocks whereas Mobil 1 and the rest are based on petroleum base stocks.

You won't find it in stores. Search where you live for a dealer or go online to www.amsoil.com.

You will not be disappointed.

 

Very interesting. I hadn't heard of AMSOIL before! In a quick Google search, here's a page I found with some comparative testing against other synthetics.

AMSOIL products and testing

I also found a reference to AMSOIL gas mileage increases:
The AMSOIL oil and air filters sound interesting, if not promising, as well. Thanks for the interesting reference.

 

I'll second an amsoil nomination.

I use it exclusively in my Harley. I don't know it's real world mileage savings on a hybrid vehicle, but it definitely is a great lubricant and my bike runs at a lower operating temperature vs. non synth 20w-50.

 

I have used Amsoil on and off over the last 9 years. In my 1997 Suburban, I DID get a 2 MPG increase after switching to Amsoil 0W-30, from 17 to 19 MPG.

In my 2004 HCH, I did not see a MPG boost at all over the Honda 0W-20. Like others have said, it all depends on the engine.

But as far as engine PROTECTION, I think Amsoil is probably best. I went 22,000 miles between oil changes in my 2002 Avalanche, just because I was in AZ and my wife was driving it in Texas, 180 miles per day to college. The miles ran up fast and by the time I got out there and was able to change it it had hit 22,000 miles. The oil did not smell burned at all, but was definitely coal black. That Avalanche engine now has 97,000 miles on it and is still going strong, so the Amsoil did it's job of protection in the long interval.

I would not recommend 22,000 miles between changes to anyone, but it's nice to know Amsoil CAN protect that long if required by circumstances. Mobil 1 now has that 15,000 mile interval oil, so the other oil companies have started admitting like Amsoil that you can go a LOT farther than the old 3,000 mile oil change myth !!!

Good luck to all !!!

 

If I really thought synthetic would make my engine last longer then I would recommend the extra cost. I don't think it helps if you follow the 5000 mile schedule. In the same respect, the extra cost of synthetic oil for an additional 1 mpg (on an already high FE car) would never pay for itself over a 5000 mile ol change.

You'd save 3.2 gallons of gas over 5000 miles of driving if you got 39 mpg instead of 38 mpg.

 

I filled my 1977 Volkswagen Scirroco with Mobil One, when it first came out. The car had over ten thousand miles at the time, so it was pretty much broken in. The first thing I noticed was a drop in oil pan temperature of about ten degrees, and the engine ran a lot quieter, and smoother. There was a gas mileage increase of between 5%-10%. The implication of this to me, was less internal friction, which implies less ongoing wear.

 

So far I've seen anecdotal evidence of the advantages of synthetic oil. I don't know how someone can see a 1 or 2 mpg difference and attribute it to the oil. I see changes of several miles per gallon between fill ups based upon my driving habits, where I drive, etc.

Does anyone know of any unbiased tests done by auto manufacturers or independent labs (not sponsored by the oil manufacturer) to back up these claims?