1 00:00:02,040 --> 00:00:07,080 Speaker 1: Welcome to brain Stuff from How Stuff Works, Hey, brain Stuff, 2 00:00:07,120 --> 00:00:10,080 Speaker 1: Lauren Vogel bomb here. Experts say you should keep your 3 00:00:10,080 --> 00:00:14,160 Speaker 1: gas tank at least a quarter full at all times. Obviously, 4 00:00:14,240 --> 00:00:16,200 Speaker 1: doing so we'll keep you from getting in a dangerous 5 00:00:16,239 --> 00:00:18,560 Speaker 1: situation where you're low on gas and too far from 6 00:00:18,600 --> 00:00:21,200 Speaker 1: gas station to fill up. But there are other less 7 00:00:21,239 --> 00:00:23,720 Speaker 1: obvious reasons to keep a little gas in your tank. 8 00:00:24,320 --> 00:00:26,480 Speaker 1: Driving on an empty tank, or even one that's getting 9 00:00:26,480 --> 00:00:28,840 Speaker 1: close to the dregs in the bottom, can cause damage 10 00:00:28,880 --> 00:00:31,479 Speaker 1: to your car in a number of ways. You won't 11 00:00:31,520 --> 00:00:33,920 Speaker 1: get very far driving on empty, but in the moments 12 00:00:34,000 --> 00:00:37,040 Speaker 1: before you do stall out, your car's catalytic converter, which 13 00:00:37,080 --> 00:00:40,199 Speaker 1: is part of the exhaust system, can be damaged. You 14 00:00:40,240 --> 00:00:42,360 Speaker 1: could also get debris stuck in your fuel pump by 15 00:00:42,440 --> 00:00:45,599 Speaker 1: running your tank too low. That's because any tiny particles 16 00:00:45,600 --> 00:00:47,839 Speaker 1: that find their way into the gas tank settle at 17 00:00:47,880 --> 00:00:49,919 Speaker 1: the bottom, and they tend to stay there until your 18 00:00:49,920 --> 00:00:52,160 Speaker 1: car is trying to grab every last bit of fuel 19 00:00:52,159 --> 00:00:54,680 Speaker 1: that it can. When the fuel pump sucks up the 20 00:00:54,760 --> 00:00:57,080 Speaker 1: last of your gas, any debris in your tank will 21 00:00:57,120 --> 00:00:59,360 Speaker 1: go along with it, and the particles can get stuck 22 00:00:59,400 --> 00:01:02,360 Speaker 1: in your pump. Or in your fuel filter. In early 23 00:01:02,400 --> 00:01:05,320 Speaker 1: model cars from the nineteen eighties and older, the gas 24 00:01:05,400 --> 00:01:08,400 Speaker 1: tanks are usually made of metal, and as they deteriorate, 25 00:01:08,560 --> 00:01:11,880 Speaker 1: harmful deposits can build up in the bottom. Newer cars 26 00:01:11,920 --> 00:01:14,760 Speaker 1: have plastic fuel tanks, so sediment usually makes its way 27 00:01:14,800 --> 00:01:19,040 Speaker 1: inside the tanks from contaminated fuel, But getting sediments stuck 28 00:01:19,080 --> 00:01:21,039 Speaker 1: in your fuel pump isn't the only way that you 29 00:01:21,040 --> 00:01:23,759 Speaker 1: could be damaging it. In some cars, the fuel pump 30 00:01:23,880 --> 00:01:26,440 Speaker 1: is located in the gas tank and the gas acts 31 00:01:26,480 --> 00:01:29,480 Speaker 1: like insulation and lubricant as it flows around the pump. 32 00:01:29,920 --> 00:01:32,520 Speaker 1: If you're constantly running your gas tank dry, the fuel 33 00:01:32,520 --> 00:01:35,119 Speaker 1: pump could be overheating, which will cause it to wear 34 00:01:35,120 --> 00:01:38,920 Speaker 1: out prematurely. But how far can you actually go when 35 00:01:38,920 --> 00:01:42,360 Speaker 1: the gas gage hits e Well, that depends on your car. 36 00:01:42,840 --> 00:01:45,920 Speaker 1: Different vehicles have the gas light configured in different ways, 37 00:01:46,160 --> 00:01:48,520 Speaker 1: though most cars will illuminate the light when there are 38 00:01:48,560 --> 00:01:50,960 Speaker 1: about two to three gallons that's seven point five to 39 00:01:51,000 --> 00:01:55,000 Speaker 1: eleven liters left. Some bigger vehicles like trucks and SUVs, 40 00:01:55,280 --> 00:01:57,600 Speaker 1: light up the empty indicator when there are about four 41 00:01:57,640 --> 00:02:00,400 Speaker 1: gallons or fifteen liters. That's about to say exteenth of 42 00:02:00,440 --> 00:02:03,600 Speaker 1: a tank left. How far those amounts can get you 43 00:02:03,760 --> 00:02:06,720 Speaker 1: is another variable that depends on your car's efficiency, you're 44 00:02:06,760 --> 00:02:09,480 Speaker 1: driving style, and whether you're in the city, on the highway, 45 00:02:09,600 --> 00:02:12,960 Speaker 1: or stuck in a traffic jam. Some newer cars have 46 00:02:13,000 --> 00:02:15,519 Speaker 1: a display in the instrument cluster that keeps a running 47 00:02:15,520 --> 00:02:17,840 Speaker 1: tally of your range or how many miles you can 48 00:02:17,919 --> 00:02:21,280 Speaker 1: drive on your current tank of gas. These displays are 49 00:02:21,320 --> 00:02:25,440 Speaker 1: pretty accurate, but again they are just estimates. Changing road 50 00:02:25,480 --> 00:02:27,880 Speaker 1: conditions or any number of other factors can affect the 51 00:02:27,880 --> 00:02:30,440 Speaker 1: accuracy of this gauge, which could leave you stranded if 52 00:02:30,480 --> 00:02:33,600 Speaker 1: you're really cutting it close. So it's a good idea 53 00:02:33,639 --> 00:02:35,640 Speaker 1: to get in the habit of filling up before you 54 00:02:35,720 --> 00:02:38,600 Speaker 1: strictly need to. That said, if you find yourself in 55 00:02:38,600 --> 00:02:41,240 Speaker 1: a situation where you're running low, don't worry. You're not 56 00:02:41,280 --> 00:02:43,760 Speaker 1: going to ruin your car. Just get into the practice 57 00:02:43,760 --> 00:02:46,200 Speaker 1: of filling up whenever your fuel gage reaches the quarter 58 00:02:46,280 --> 00:02:54,280 Speaker 1: mark and you'll be fine. Today's episode was written by 59 00:02:54,280 --> 00:02:56,920 Speaker 1: Sherry's three Wit and produced by Tyler Klang. If you 60 00:02:57,000 --> 00:02:59,760 Speaker 1: enjoy our show and also like wearing T shirts, check 61 00:02:59,760 --> 00:03:02,280 Speaker 1: out our online shop at t public dot com. Slash 62 00:03:02,320 --> 00:03:04,239 Speaker 1: brain Stuff we've also got a bunch of back to 63 00:03:04,240 --> 00:03:07,320 Speaker 1: school stuff like laptop cases too, and of course, for 64 00:03:07,400 --> 00:03:09,760 Speaker 1: lots more on this and other revd up topics, check 65 00:03:09,760 --> 00:03:23,359 Speaker 1: out our home planet how Stuff Works dot com.