Ray Magliozzi
Dear Car Talk:
My question is about gasoline. The conventional wisdom I’ve always heard is that brand-name gas (Chevron, Shell, etc.) is better for your engine than what is sold at discount/mom-and-pop gas stations.
Is that true? Is it worth the extra money? I’d like to save a few bucks but don’t want to be penny wise and pound foolish. Thanks.
— Mickey
Originally, all gasoline comes from the same place, Mickey: dead dinosaurs. From the ground, crude oil goes to a regional refinery where it’s turned into gasoline. Then it sits in huge storage tanks. At that point, all gasoline is still the same.
But once a gasoline retailer buys a batch of it, that’s when things change.
When Shell, Chevron, or Fred’s Burritos and Gas orders a supply of fuel, the refiner then adds a package of detergents and additives specified, and paid for, by that retailer.
So, while Fred’s Burritos and Gas may tell the refiner to just add the minimum-required detergent package because they compete on price, other retailers may specify a more robust additive package.
How do you know which retailers have better gas? Around 2004, a group of carmakers who were concerned that dirt and carbon deposits from gasoline would shorten the lives of their engines (and increase their warranty costs), got together to agree on a gasoline additive package that met a higher standard.
This became “top-tier” gasoline. Top-tier gas has a package of detergents and additives that meet the cleanliness requirements set by Audi, BMW, Ford, General Motors, Honda, Mercedes-Benz, Subaru, Stellantis, Toyota, and Volkswagen. Each of those manufacturers recommends top tier gas for their vehicles.
Does top tier make a difference? Well, the only good evidence we have so far comes from a study conducted by AAA in 2016. They had an independent lab test new engines using three top tier and three non-top-tier fuels.
And after the equivalent of 4,000 miles of use, the non-top-tier engines had 19 times as much carbon on their valves as the top tier valves.
So, based on the evidence so far, we’d have to recommend top-tier gasolines. Especially if you drive one of the above vehicles, or have what you consider a new or valuable vehicle.
How do you know which brands have top-tier gas? The easiest way is to go to toptiergas.com and look up the brands you drive by most often.
Most, but not all, of the major brands — including Costco — are now top tier retailers. A number of smaller, regional brands subscribe as well. And if a company agrees to be a top-tier retailer, every octane fuel they sell must be top-tier. So, there’s no need to buy premium if your car doesn’t require it. Regular grade will have the same package of additives and detergents.
So that’s the story, Mickey. Look it up and buy cleaner gasoline when you can.
Got a question about cars? Write to Ray in care of King Features, 628 Virginia Drive, Orlando, FL 32803, or email by visiting the Car Talk website at www.cartalk.com.
