Dear Car Talk,
My Friends, the Bisios, were traveling to Sun Valley, Idaho from Portland, Oregon for the New Year holiday yesterday in their 2004 Lexus LX SUV. While Mario, the Dad, was driving through a particularly desolate and mountainous stretch of I-80, Anne, the Mom, noticed the low fuel light was aglow and became very concerned because she’d been told when she bought the car that she must never run out of gas as the car would not start again and the engine would suffer serious damage. Of course Mario continued on determined to make the next gas station which was about ten miles out. The car has a feature which informs the occupants of the potential distance left in the tank, this read “7 miles”, and Mario agreed to pull over when it neared zero. With the distance indicator approaching the dreaded “0”, and his family screaming to stop, Mario, with great reluctance, ditched just short of the station, by less than 2 miles and called AAA.
Our questions are the following: 1) Were they correct to stop and would they, had they not stopped, have incurred a multi-day layover at the Boise Lexus dealership? And, 2) Is the “Trip Meter” accurate? Does a Lexus run out at “zero” or have the engineers designed in a cushion, and if so, how much might they have allowed? My wager is they would have made it. Please advise.
Kindly,
Kirk Squier
My guess is that a “cushion” has been programmed into the system.
Then again, these high-tech fuel mileage readouts tend to produce gas mileage figures slightly better than reality, so it is also possible that the system does not have any leeway built into it.
I suggest that you advise your friends that, if they are in unfamiliar territory, it is probably a good idea to fill the tank shortly after the needle drops to the 1/2 mark on the fuel gauge if they want to avoid this experience again.
This is a game of chicken which people like to play to get their juices flowing. It can be pretty deadly in winter and very unpleasnt in the summer.
For what it’s worth, my Toyota has such a warning light, and I tried it out on a road I knew well.
Arriving at the gas station where I was going to tank, I discovered they had stopped selling gas and just sold oil, antifreeze and food. There was another gas station a little further, but, unlike your “adventurous” friend Mario, I called the AAA and had them bring me some gas while I had a snack and a coffee.
To answer your question, when the light goes on you probably have 1-1 1/2 gallons left in the tank, and yes, Mario could have made it to the next station. No gas gauge or warning light is accurate enough to say EXACTLY 7 miles remaining.
So, I am hereby “advising” you that it’s really stupid to keep driving when the gas light goes on, and running out of gas with any car is troublesome, and with a diesel it’s deadly, and can incur a high expense.
The way to find out how much reserve you have is to fill up at the exact time the light goes on, see how much it takes and subtract that from the volume of the tank listed in the OWNER’S MANUAL. That may not give you the exact answer, since there is a low part of the tank where the fuel pump probably can’t reach.
In-tank electric fuel pumps aren’t very forgiving when the gas tank runs out. The gas in the tank acts as a coolant for the fuel pump. When the gas gets very low in the tank it causes the fuel pump to run hotter. If the gas runs completely out of the tank, the wetted parts of the fuel pump are no longer being lubricated and the fuel pump is destroyed.
Tester
The cushion is the inacurracy in the guage which is on the plus side likely. My Subaru when it shows 40 miles to empty really means only has a bit less than 2 gallons left. It gets about 23 MPG.