Finally happened, broke down after decades of traveling between DC and Norfolk VA on US 301 and 17, near Gloucester Va. After the tow and a local garage looked at it - 2001 4.6, 87,000 miles. It's a 4X4 so I have the 30 gallon tank. The verdict was replace the fuel pump and so I did, since I wanted to get home to DC.

Have seen and heard several posts and other folks comment again on not letting the tank get low, as the fuel cools the pump, which I tend to do, as I can make the round trip and I am just about empty.

I know Alloro has posted, so chime in please with the latest info you have - I take it no lower than a quarter tank or what else have you found - do I really need to go no lower than a half tank.

Anyway, thanks much for the info - I did use the search function and that's what has prompted me to ask for more info from all of you.

Mike

 

I don't believe there is any validation to that line of thinking. If it were factual there would be cars and trucks on fire everywhere you look. The fuel in the tank does cool the pump but it is not critical.

 

Yes you can go that low. My remark about low fuel levels causing a short lifespan of the fuel pump is based on people that never fill their tanks. I've seen a lot of people that wait until they're near E and then stop and throw 20 bucks in; over and over and over. It's this behavior that keeps the pump out of the fuel all the time that will reduce the lifespan of the pump. If you're taking a trip, then by all means go ahead and run the tank from F to E over and over, there's no harm in that.

 

Right, of course...I must've said it just because I had nothing better to do at the time.

 

I have a freind at a dealership who is one of the mechanics, his take is in the summer where the temp goes up they will see a lot more pump replacements. In the winter not so many, so I think the idea of cooling does carry some weight. How much who knows. So he recomends keeping at least a 1/4 of a tank in the summer, winter it is not as important.

 

That would not be surprizing as the ambient temperature is higher and people do a lot more travelling in the summer, working the fuel pump harder. Running a low fuel level would likely keep the pump motor a bit warmer and contribute to an early death of the pump. I just suspect everything that wears out as a plannmed obsolesence by the manufacturer. I know that is not completely the case as todays cars are far more refined than they were 20 years ago, it's just that they have so much crap built into them that it is difficult for the DIYer to diagnose and then work on the vehicles.
They make remarkable power for the engine size but that onlly make you wonder how much more could be had without all the sensors, computers and anti-pollution devices they are equipped with. And then there are the items that are changed slightly for a newer model that does the same job as a similar item on a slightly older model and it will not interchange with yours. The air suspension comes to mind first as the air springs are not available from Ford for the '99 to '02 and again for the '03 to '06 Expeditions and Navigators as well as several other critical parts for a large number of cars and trucks that are in daily use. Just thinking about that makes one wonder about how Chevrolet manages to still make and sell parts for cars built in the '50s and '60s.
Now that I've had my rant for the day, I do feel better.

 

Not that it matters, but I was always told if you run it on 1/4 tank or lower all the time your pump is more likely to pick up all the trash, rust, or anything else that may be in the tank. And it makes sense considering theres less to choose from in the tank rather than having a more full tank allowing more room for any of that junk to be able to float away from the pump.... May seem kinda stupid, but at the same time its simple theories for both explanations of the pumps not lasting as long

 

Water, rust and trash are usually at the bottom of a fuel tank as is the pump or fuel pick-up, therefore you are still likely to pick that stuff up if it is in the tank. Not too many years ago there was a bung to drain the fuel when it was suspected to be contaminated. I don't think that is available in any brand of vehicle any longer.

 

My theory has been, especially in the winter time, to keep the tank filled as often as I could, to reduce the condensation and minimize the rust formation.

(Back in the day we had a 1971 German built Mercury Capri - the fuel tank was visible in the trunk under the package tray. If you opened the trunk on a brisk winter morning you could determine the fuel level by the frost on the outside of the tank!!)

 

You don't need no steenkin' fuel gage with that car, at least.

100% correct in keeping the tank filled to keep condensation from forming and the rust that comes soon after. All of my '60s Mustangs and Comets had the rust and leak syndrome.

 

Hey, thanks folks, gives me something to think about - no reason I can't fill up at about the 1/4 tank level anyway. Seems much smoother now - certainly smoother than running on leftover fuel in the rail, and I got the full replacememt Motorcraft pump since I was going to spend a lot anyway.

Mike