My fiance' has a 2005 X3 3.0V6. She is convinced that if the fuel gets below 1/8 of a tank and the light comes on that damage can be caused if you drive on it.

I think that as long as there is fuel in the tank and we're not running it dry then it can wait a few miles until we get to a convenient time and place to fill up.

This issue has caused us to get into arguments! I'm sooooo sick of debating it with her because she thinks she knows everything so I want to know from the real experts.

...anyone?

I don't see how damage can be done, It's running on the same fuel it would run on if it was full.

I don't think is as true as it used to be, but running the tank down to the reserve light has been know to shorten the life of the pump or earlier BMW's. And there's some risk of the pump sucking up any debris that might be in the tank. And then there's the possibility that the light could fail or that the quantity could be on the really low side before you notice the light... But in any event it won't hurt the engine, though it could be a bother and be embarassing to run out of gas.

The safe approach would be to refill when the gage gets down around the 1/4 mark.

We never run it dry or anything of the sort, it's just that the owner's manual says that you shouldn't wait much after the light comes on to fill it otherwise damage may occur and that's what worries her.

I'm still convinced that as long as it's not being run dry then it's fine to take it a few extra miles until you get to the right gas station or wait to do it until you're on your way home from work instead of to work.

I've heard of engine damage if you completey run out, in some cases, but not from using existing gas when 1/8 is left.

My fiance' has a 2005 X3 3.0V6. She is convinced that if the fuel gets below 1/8 of a tank and the light comes on that damage can be caused if you drive on it.

I think that as long as there is fuel in the tank and we're not running it dry then it can wait a few miles until we get to a convenient time and place to fill up.

This issue has caused us to get into arguments! I'm sooooo sick of debating it with her because she thinks she knows everything so I want to know from the real experts.

...anyone?

It won't do engine damage. However people think it will because they get a check engine light. Check engine light comes on and stores a fault for lean misfire cause by low fuel.

It won't do engine damage. However people think it will because they get a check engine light. Check engine light comes on and stores a fault for lean misfire cause by low fuel.

What he said.

Also, people need to stop spreading the myth that running the tank low lets the pump pick up debris from the bottom of the tank. The fuel pump always pulls fuel from the bottom of the tank!

Also, people need to stop spreading the myth that running the tank low lets the pump pick up debris from the bottom of the tank. The fuel pump always pulls fuel from the bottom of the tank!
Yes, the pickup of the pump is very low in the tank. But as long as there's a good bit of fuel in the tank the velocity of the liquid along the bottom of the tank stays low. However if you run the tank almost dry the velocity of the liquid increases to the point that it can transport debris towards the pump.

better get that V6 in the shop! its all messed up.


dont listen to the intardnet mumbo jumbo. if you think its a V6, then dont go less than 1/4 tank :)

I got the best idea!!! stop being cheap and procrastinating and just fill the damn tank up haha. real spit. peace!

Full tank + Less cash in wallet = No arguments. lol

If you live up north where it gets freakin cold, I would avoid driving it into the super low reserve. Won't hurt the engine really, but gas can freeze. Like was said, it sets a fault for misfires when you run it out, but no engine damage is gonna happen. You run it out when you do a compression test forinstance, and thats done on purpose. The tanks are saddle tanks, half on the left up and over the driveshaft, half on the right. Not gonna get much velocity stir action going, and the pump and siphon jet pump both live in little holes anyway so if there is crap in there its already in there. Thats what screens, and filters are for. If you get the good gas from good gas stations, not gonna get much crap in the tank, since they are plastic. So to make a long story short....won't hurt it, but might set a light.
~CHUBBIE~

i guess its possible to theorize that because most fuel pumps are cooled by the gas in the tank if you run it low to the point where the top of the pump doesnt have fuel sloshing over it it wont disperse its heat very well which in turn could damage the pump....

furthermore if you start chuging and sputtering around corners because your not picking up fuel then it could cause problems because of an unesacarily lean condition in the engine. running lean will result in engine damage

neither of these would happen at 1/8 a tank tho

It would be really hard to slosh gas away from both the left side siphon jet and the right side fuel pump. The left side has a pump that pumps fuel to the right side thru a tube directly into the pick-up for the pump. You'd be on fumes by the time you had to worry about sloshing. It wont run lean for long.
~CHUBBIE~

aight i didnt quite know the design of the BMW fuel pump system and how it works, but for safteys sake fill the damn tank up at 1/4