We get asked this question all the time — I just got a new Tundra and I want to treat it right — should I use synthetic oil? If so, should it be full synthetic or synthetic blend? The answer is complicated. Since synthetic oil has fewer impurities, better properties at high temperatures than natural oil, slightly better viscosity, and is more resistant to breakdown, synthetic is better for an engine. However, whether or not it’s better for your engine depends on a few things.

First of all, are you zealous when it comes to changing your oil? i.e. If the manual says to change your oil every 5000 miles, do you have the oil changed at 4999.9? If you follow an oil change regimen, chances are you won’t benefit from synthetic oil. Synthetic oil is highly resistant to breakdown and sludge forming. However, most oil won’t breakdown unless excessive time and/or mileage passes between changes. Because most the benefits of synthetic oil over regular oil don’t show until the oils subjected to adverse conditions, you really won’t see any benefit from synthetic unless you stress the oil. If you are the type that might forget an oil change (shame on you), or if maybe you don’t get to changing your oil right at 5000 (or within 500 miles of 5000), then you can buy a little insurance against engine damage by using synthetic oil.

Case in point. My grandmother, who drives a few thousand miles a year (less than the Toyota recommended 5000 miles between oil changes), uses synthetic. Why? Because her oil can go more than a year between changes. Unlike natural oil, synthetic oil will last more than 6 months without any breakdown in effectiveness. So, if you (or someone in the family) is likely to exceed the 6 month time between changes OR is less than perfect at getting oil changed on time, a synthetic oil makes sense.

If you’re good at changing your oil on time, there’s really only one other common reason you would want to consider using synthetic. As natural oil gets hot, it starts to breakdown. The longer it stays hot, the worse the breakdown. So, if you regularly operate your vehicle in such a way that the engine temperature is always high, you should run synthetic. For example: Letting your vehicle idle for hours at a time (like on a jobsite) will overheat the engine. Because you’re not moving, there is no high-speed air circulating around the engine to keep it cool. In this case, excessive heat can build and normal oil will break down. Also, constant operation in high ambient temperatures (like the desert) or at high altitudes (over 10k feet) will also lead to higher engine temperatures. High temperature desert air has poor cooling properties, and while the air above 10k feet is usually cool, it’s “thin” and also has poor cooling properties.

The last example of a high-temperature use that would benefit from synthetic oil would be racing. Hopefully, if you’re racing, you’re using the best oil you can and changing it often.

Some experts suggest synthetic oil in stop and go traffic. I disagree, but they may have a point. It depends on your typical drive and just how much “stop” is mixed in with your “go”. If idle is excessive, then you can go synthetic. There is also some advice out there stating that if you only drive your vehicle short distances, you should use synthetic. The theory is that synthetic coats the engine better in a short time period than natural oil. In my opinion, if you only drive short distances, synthetic oil will not save your engine. Short distances are bad because the engine never gets a chance to fully lubricate and cycle the oil in the system. With modern engine tolerances being so high, I really don’t think synthetic will make much of a difference by sticking to all your parts better than regular oil. My advice to people that only drive short distances - stop it. Drive an extra 10 minutes. Join a carpool. Take the long way home…etc. Stop hurting your motor.

If you do decide that you would see some benefit from running synthetic oil, be conscious of “synthetic blends”. While many manufacturer’s have a synthetic blend as their standard oil, the term synthetic blend is not regulated. Any mixture of regular and synthetic oil is considered a blend, even if it’s just 1% synthetic and 99% regular. If it’s not a manufacturer provided oil (i.e. Motorcraft, Goodwrench, Genuine Toyota Motor Oil, etc.) then it could be a very low percentage of synthetic in the oil. Some companies will state the percentage, but you’d be surprised to find that big names like Valvoline, Penzoil, Quaker State, etc., have very low percentages of synthetic in their blended oils.

Last but not least, what does Toyota have to say about synthetics? “Any oil that meets API standard specifications can be used in your vehicle.” That means normal oil is just fine.

Bottomline: Unless you’re subjecting your new 2007 Toyota Tundra (and the oil that’s in it) to extreme conditions, save money and use regular oil.

Popularity: 6%