Q I just got the oil changed in my car and was asked if I wanted regular or synthetic. Which is the greener choice?
A It depends on what you mean by "green." When it comes to picking motor oil, other factors come into play, including how much you like your car. "It's a tough question for a definitive answer," said Mick Jost, senior scientist with Minnesota Technical Assistance at the University of Minnesota.
"In general, most experts would agree that synthetic is [for now] the lesser of the two evils," writes Eric Leech for Planet Green in Denver. That's mostly based on the fact that conventional oil is derived from petroleum. However, synthetics contain chemicals that are no less harmful to the environment, he added.
Synthetics also can last longer than conventional motor oil, so in that sense, they are greener because you don't have to change oil as often, said Jost.
The traditional standard is an oil change every 3,000 miles, he said, but there are studies that say this interval can be increased, even with conventional oil. Some say you can go 7,000 miles before changing conventional oil. With synthetic oil, it supposedly can stretch to 20,000 miles. That means a lot less waste.
You may think the waste oil doesn't matter so much because it's recycled. But when it's collected for proper disposal, it's either re-refined and added back to the base stock, which takes energy and lots of filtering, or it's burned by industry to recover the energy. In that case, the carbon is released into the atmosphere. Either way, it's gone, said Jost.
Other reasons for choosing synthetic oil, according to Leech, include:
• Synthetics have a lower volatility and therefore do not vaporize out the exhaust as quickly.
• They produce less resistance in the engine, so they offer more horsepower and overall efficiency for the engine. This added horsepower in return means that the engine will be able to perform at the same level as before, but using slightly less gas.
• The manufacturer recommends synthetic oil. If you value your car and its warranty, you should act accordingly.
On the other hand, if you're thinking of "green" as in what's in your pocketbook, then conventional oil comes out ahead. A synthetic oil change costs more than conventional -- sometimes twice as much.
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