I care for all of my engines similarly, fuel system cleaner and upper cylinder lubricant, if stored for long term, Stabil marine to combat ethanol, thats it. I guess it was just an aside me and TiAg got on to show how many uses we have for fuel additives (Techron and Lucas UCL) in my case

Yeah, we were off-topic with details of what we use in ALL engines in households.

Have to agree with bc here. In fact, the wrong stuff will gum up your top ring (thing Marvel Mystery Oil). I stick with Shell gasoline and stay away from additives. Seems the people who run them a lot replace O2 sensors and catalysts more often. My sensors went 260,000 miles and I'm still on the original cats.

The exception for me is fuel stabilizer for anytime the fuel won't be used for more than three weeks. Evinrude released a white paper several years ago that showed ethanol began to separate from the fuel at three weeks and could be fully separated, and sitting at the bottom of the tank, after six weeks.

2002 X5 3.0 280,500 miles
2004 325i 120,000 miles

You should worry.... less fluid heats up much faster/hotter. Also, the part of the pump that is not submerged cannot conduct heat directly to fuel. I'm not saying your pump is going to explode tomorrow, it's just unneeded wear.

It's cool to know how far one can push it. Seinfeld rocks. I know I can get 390-ish miles per tank. It's a good gauge to the health of the motor. However, I choose to fill up between 1/4 and when the light comes on.

I'm lucky to get 400 on a 1/2 highway tank. Best I've seen is 495 fully freeway. I am averaging 15.8 right now.

"Well I don't agree, I'm still gonna do it Jerry", said Cramer. I understand the heat kills stuff but I don't think it is getting hot enough to matter. I don't see it as a significant wear factor as anecdotal evidenced by still running the original pump. :iagree: about mileage being a good gauge of health of engine. 14 miles to go means I have at least a gallon in the tank. Maybe the pump is still covered with a gallon left? Another reason I do it is that I'm guessing that when sediment or water in the tank causes a problem it is because it was allowed to collect over time. Running it down is a kinda sick fun.

Just kidding. Many times the off topics are more interesting than the on topics. All I do with lawn equipment is use regular gas that has Techron in it.

I try not to run my X down past the light. Ive done so in the past (hypermiling with an x-5 is an oxymoron!!) and burnt out a fuel pump, plus had a nasty tow bill too!
my best advice, is, fuel helps keep the pump running cool, a cool running pump runs better. A running fuel pump means i dont have to spend the time and $$$ on a new one!! while its an easy job, i would rather not have to change out the pump!!
I buy a 5 gal jerry can of premium for my lawn tractor, mower and mixed fuel stuff. Techron is great stuff, Ive also had good success with Seafoam too, and at the end of the season, all the toys get stabil!