Best synthetic oil

Hello guys. (Really enjoy the show), I have a 2005 Sequoia 4x4 and was wondering what you’d advise regarding the best synthetic oil on the market. I’ve been looking into Amsoil…and the extended oil changes. Thoughts? Keep up the great sense of humor and the fun approach to automotive issues. Thanks a million, riversongwriter.

I’m sure Amsol is good, but not sold in my area. I use Mobil 1 which is a true synthetic oil with a polyalphaolefin (PAO) base stock. The cheaper synthetics use a regular mineral (dino) oil that has been hydro-treated.

Use the right viscosity range and your Sequoia will run happily fo many years.

You are NOT talking to Tom and Ray. We are just listeners to Car-Talk like you who share a common love of cars/trucks.

The ONLY oil I know of that is a Group IV base stock is Amsoil. After loosing their lawsuit with Castrol, Mobil-1 started using Group III as their synthetic oil.

Me thinks you are worrying too much. You really do want to use an oil that meets or exceeds the oil specified in the owner’s manual. But the real life difference to your car between any of those oils is minimal at best.

Modern cars have very very few oil related problems, once you eliminate those who did not change the oil, did not check the oil level, did not change the oil as recommended in the owner's manual, or did not use a recommended oil.   

I am over 60 and I can remember when there were real problems related to oil, but not today.  

Change the oil as recommended using the recommended oil (along with a filter change) and check the oil to make sure it does no go low and you are just not going to have oil related problems that using any different oil could have prevented. 

 You can look at all the advertising claims and listen to all those who use this or that oil or change it every 2,000 miles but in the end, there is no real difference in results.

[b]It’s Mobil 1 For Me.[/b]

I change my own oil. I stock up during Advance Auto’s sales, like the one that goes through Wednesday, March 25. Five quarts and a Mobil 1 oil filter for less than $30 can’t be beat. I get a year’s worth for each of our cars. They even take back the used oil!

At one time, synthetic was nearly four times as expensive as dino oil. Now I’m paying less than double ($30 - $oil filter = cheap). You can extend the intervals and the savings is even greater. Register your purchases on Mobil 1’s site and earn savings certificates.

It doesn’t get any better than that!
America, What A Country!


Synthetic oil is a waste of money unless there’s a specific application for it.

What I get a laugh out of is, a lot people on this board suggest that people look in their owners manuals when it comes to service intervals. But you find those who use synthetic oil, they ignore the recommendations noted in the owners manual for oil change intervals. I’ve never figured that one out? The owners manual makes no distinction between synthetic and regular oil, and when it should be changed. And the manufacturer of the synthetic oil states on the container that the oil should be changed per the vehicle manufacturers recommendations.

Do people who use synthetic oil, all of a sudden hear a voice from a higher authority than the auto manufacturer, that the recommendations stated the owners manual can be ignored because you are now using synthetic oil? I never hear that voice when I use synthetic oil in my Mazda turbo, and change the oil per the recommendations stated in the owners manual.


How true, synthetic oil isn’t a cure all. Some cars require it and it comes already in the crankcase when you buy the car. My feeling is that there are still a lot of things in the used oil that need to come out regularly, like moisture, carbon byproducts, acids, depleted additives, etc. and while synthetic oil has a real distinct advantage in some areas, especially heat breakdown and shear resistance, it still needs to be changed per the owner’s manual. Not to do so would possibly violate warrantee requirements. So that is why the owners manual is the bible on oil changes. All of the synthetics are similar in performance at the designated change intervals. Some mfgrs. do recommend certain synthetics (like my wife’s BMW wants you to use only the German made Castrol 5W-30 synthetic and not the domestic!). This has a lot to do about the way BMW sold cars, with all the required maintenance included in the deal. They even got rid of the tranny dipstick and said their tranny fluid was “lifetime fluid” and never needed changing. What a load. This just minimized their cost and the auto trannies they used were mostly GM made in France (and GM trannies don’t last a lifetime, especially if you don’t change the fluids regularly). Use Mobil 1 or Castrol and change it when due per the manual and you will be very satisfied.

I follow my owners manual(severe interval for oil) and it does not prescribe synthetic for high sprung turbo Subaru’s. Interestingly enough I got a letter from Subaru recommending that all turbo cars are considered severe for oil and to use 3750 miles(already was). They actually prescribed 7500 miles on dino for turbo’s in normal conditions.

Not sure if owners manual is always the “bible”. Same was true for Toyota engines of the early 2000’s sludging up and VW 1.8T’s of the early 2000’s too. Same deal too long of interval without specific oil spec.

Hey! You Talk’in To Me?

I’m not advocating going beyond the manufacturer’s recommendations, but for people who change their oil at shorter intervals, I believe synthetic is a good choice for people extending their changes out to the manufacturers requirements. Some folks who do no severe driving change their oil every 3,000 miles. I think some oil change shops and even dealers try to convince people that this is required.

I agree. Go by the book.

Since my manual recommends synthetic for extremely cold temperatures, like the ones where I live which reach -30F during our looong winter season, that’s what I use. The manual says it gives better cold start protection. Since I don’t like to change back and forth, I also use the same type of oil all year around.


Synthetic oil was developed for fleet users so that they could extend the change intervals and reduce staff in the motor pool. It is highly unlikely that you will notice any benefits at all. Use whatever is recommended in your owner’s manual and enjoy your truck for a few hundred thousand miles.

There is a special board for motor oil obsessives, It goes on FOREVER. Synthetics excel in only two areas. Extreme cold and extreme heat. That’s what they were developed for, jet turbine engines. The first synthetic for cars was called Conoco Polar Start. Came out in 1969 or 1970…Synthetic base stock offers no benefit in lubrication over mineral oil base stock. In most aspects, mineral oil is a superior lubricant. Through the use of expensive additives, synthetic oil can indeed be made into a superior lubricant. This, added to its naturally better viscosity spread, give it an advantage in certain applications. But for the average motorist, it’s hard to justify the added cost…

I concur. Time sink central for motor oil.

I use WalMart SuperTech synthetic. I get all the benefits of synthetic at dino oil prices. End of discussion.

Last I checked, not all Amsoil products are API certified. That is not saying they are of better or worse make (probably better from the word of mouth I hear), but that by using products without the API seal of approval you may void the warranty of a new car.

I use Mobil 1 in my Acura and Castrol Syntec in our Olds. I’m happy with how these oils perform in these cars.

No warranty can get voided entirely. However a maker can deny a claim that they believe is related to improper maintenance or parts used.

But do you get enough benefits to justify the extra expense? The extra expense compared to WalMart’s equivalent petroleum product, that is. There is no real way to know, since you can’t use both in your car at the same time and make a comparison. I doubt that you get any measurable benefit. But if you feel better about it, keep using the synthetic.