The dirty little secrets of cheap gasoline

[MUSIC] Hey folks, Cooley here with another one of your emails about high-tech cars and modern driving. This one comes in from Anotherguy2741 who says, in watching your recent video on mid-grade fuel it made me wonder about your view of the quality of different brands of fuels, as in the major brands like Exxon, Shell, etc. Versus store brands that are sold at Walmart, Kroger, or the no name gas station, it's a very interesting topic because once you deal with the greater [UNKNOWN] if to figure out how to brand matters are bit right, there is two big components over the cause what you are putting you think well maybe I'm not critical enough which no one ever accuse me of when it comes to cars. But I think most of the gasoline you can buy today is probably just fine. Let me explain what I mean. First of all, the gasoline station network is supplied by a matrix of suppliers. Your local station probably gets their fuel from a jobber, kind of a middle man. He drives those tank trucks and brings them from the refinery or fuel depot to the gas station. That's gonna start to mix up your suppliers because isn't Exxon delivering to Exxon, Mobile to Mobile, Chevron to Chevron. And it is whole lot of cross pollination going on in there and a lot of the brands that are making fuel don't even have gas stations. So where are they sending it? In fact, brands on gas stations are more about minimart loyalty and captive charge card acceptance, than they are about the brand of gas you're getting out of the ground. Just look at the list of California's biggest refineries, and you'll see there isn't anything close to an exact match, For every one of those to a brand of gas station out there. Tesoro is a huge supplier here in California, but we have no stations by that name around here. They control ARCO, but they must sell to others. Mobil stations are fairly common in the SF area, but I don't see any ExxonMobil refineries on the state list. And Chevron is absolutely huge. How much do you want to bet there's Chevron gas in a bunch of non-Chevron pumps? Next up, look around and as best as you can tell pick a good retailer. A solid, well-maintained gas station. Now back in the early 80s, 60 Minutes blew the lid off this story. Two or three our of every ten gas stations in this country are leaking gasoline into the ground. Tons of gas stations around the US had leaky underground storage tanks. Those things were polluting ground water all over the place and allowing water and sedament into the tanks, means it ends up in your tank. Not good for your car for sure. Then the EPA got some new laws as a result of that expose, some new enforcement authority, and they went from having about 60 or 70,000 known leaky underground tanks around the country, to fewer than 8,000 25 years later and presumably a lot fewer today. One good indication is to look around for gas stations in your area that may have been shut down, dug up, and retanked lately. Then when they reopen you've got a pretty good feeling that they are not selling you fuel full of sediment and water anymore. The third thing is look for stations that sell what's called top tier gas, or diesel, or both. It's a labeling program but what it means is they're selling fuel certified with input with carmakers and compliance by refiners. To meet a higher level of detergent content that what is required by the EPA. Now, detergents in fuel have been gas industry marketing BS for decades, but today that's getting a lot more attention because of some intricacies of new engines. A lot of you ask, does my engine have one of these fouling issues that direct injection engines reportedly suffer from? And it can be an expensive repair in some cases. Here's what's going on. Here is an engine that doesn't have direct injection. The way this used to work was fuel came in from an injector right here in what's called port injection. It gets blended with air coming in another channel and that mixture blast by the intake valve, a key part of any cylinder in a car. And constantly cleans it. Because air and gas, before it's combusted, it's a solvent. It's a handy way to clean the back of that. It naturally keeps itself relatively clean. now here is a direct injection motor. This is a Ford ecoboost four cylinder. It's a little hard to see, but if you look down here this is where the fuel injector is now. This is direct injection. It is parallel or alongside if you will the engine's valves. Not ahead or upstream of them. As a result it's nice cleaning air fuel mixture is no longer spraying the back of the intake valve. At least not much. Now you see all of that will depend on the physical layout of all these parts in here. They vary by engine and by the timing in the engine control software. How much the valve opens, when and for how long? How much fuel is delivered in what kind of spurts, and for how long? There are a lot of variables here. You're not gonna figure out the gas pump, but this potential for more fouling and less cleaning of the intake valve is part of the reason people are getting very concerned about putting clean, quality gas in their car. Bottom line at least half the things that determine the quality of the gas going in your car cannot be determined by the brand on the station and a whole lot of things that can determine the quality are invisible to you.