2010 And Later Models
Prius models built before 2010 were equipped with a bladder tank that kept the vapor space above it at a minimum. Depending on the temperature and loss of elasticity, a full tank might hold less than the 11.7 gallon rated capacity, leading to unpleasant surprises.
My understanding is that the bladder tank was replaced with a rigid tank in the type 3 models - 2010 and later. I had a 2010 and now have a 2012. On the 2010, when the single bar first began blinking, it would take 9.4-9.5 gallons to fill up. With a rated capacity of 11.7 gallons and a fuel economy of 50+ mpg this would mean more than 100 miles to empty.
On one tank with excellent fuel economy (56+ mpg), I decided to push my luck and keep driving until I racked up 603 miles. The fill up took 10.8 gallons suggesting 0.8-0.9 gallons were left in the tank. Back calculating, it would appear that about 2.3 gallons were left in the tank when the light started blinking giving 115 miles to empty at 50 mpg.
Results may vary.
Story replies
Nice stats! Thanks for sharing. I have a 2010 but never let it go below 2 bars; Im worried about bad gas gumming up the fuel pump.
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I have a 2010 Prius. My gas light was flashing last night but only drove another 15 miles to home. I figured I won't be going anywhere today with the heavy snow today in DC. I will get gas the next time I go out close to home. My cut off is about 60 miles after the gas is flashing, but last week, I went almost 65 miles because I was in an area without any gas stations for a few miles south of Annapolis. See my next story in the next comment.
October 2, 2014 was my record to put in the car, which was 11.29 gallons. I was heading back to my office that afternoon, and the gas light was flashing shortly before I got on west on I-66 from 495; about 8 miles from my office. I figured I would get gas after work between Fairfax and where I was going that evening in Arlington. When I got back to the office at about 3:20, my boss realized that the place in Laurel charged us too much and that we had a credit. It was only my second day at that job. He told me to go back to Laurel now, I told him that I won't make it by 5 PM, the traffic on 495 from Tysons Corner to I-95 in Maryland was causing the time to be 2 hours. He said, 'Go the opposite way on the beltway.' So, instead of driving 23 miles from 66 to 95, I drove the opposite way 41 miles. In this emergency situation, I used the 495 Express Lanes, which he reimbursed me for, and I had record speed of 99 at one point. I zipped around the cars in PG County, and I got there a little after 4:45. During this ordeal, I was also a nervous that I could run out of gas since I was going a good distance and driving aggressively. Afterward I took care of it, I went to the nearby Shell station and got 11.29 gallons in the car. Thankfully, there has not been a work day quite as tense like my second day there.