In my experience, it varies from car to car. What is more important is how far the car will go after the light comes on.
So do an experiment to see how far YOUR car goes after the light comes on. Get a spare gas can that holds at least 3 gallons of fuel, fill it and put it in trunk. Read odometer when light comes on or reset trip odometer and drive car until it stops or you notice fuel starvation. Read odometer again and subtract the the original reading from the out of gas reading. Refill car fuel tank from from spare gas can and continue on your trip.
Now you know how far YOUR car will go on the reserve.
My '79 300 SD would always go 50 miles after light came on. So the reserve was about 2 gallons. However, the light doesn't work anymore so I have to keep more fuel in the tank now.
P E H
Last edited by P.E.Haiges; 03-31-2003 at 11:06 AM.