Yes. The fuel in the tank helps cool the fuel pump. Tell him to stop or start saving for a premature fuel pump replacement.
Then, of course, there is the danger aspect. I don’t want to be around when it does finally run out of gas - just as he’s riding down the highway at 70MPH with a semi bearing down on his bumper.
And then there’s the - what’s the point? Its just dumb. There are only downsides.
This can be potentially harmful to the car, and even more harmful to the operator. If the car actually runs out of gas, you obviously won’t be going anywhere and will either have to grab a gas can out of the trunk, walk to the nearest gas station, and deliver fuel to the car, or call someone for help. If friends or family are not available, you will need to call a wrecker to either tow your car to a gas station or deliver fuel to you at a grossly inflated price. My brother used to perform road service for semi trucks, and said they charged no less than $150 (usually more since the $150 job was less than half a mile away from the service station) to deliver 15 gallons of diesel fuel to a rig that ran out of fuel, and towing companies will probably be priced similarly. Mechanically speaking, fuel starvation (i.e: running on fumes, literally) will force the engine to run very lean, causing preignition (pinging) which could damage pistons and combustion chambers over time, and damage the catalytic converter(s). There is also speculation that chronically running the tank below a quarter tank could cause the fuel pump to overheat since the gasoline acts as a coolant for the pump, leading to premature failure of the pump, but it is a topic of debate amongst mechanics and has not been proven or disproven. I would suggest keeping more gas in the tank for peace of mind and to avoid being stranded over something perfectly preventable.
I hope neither of you ever needs a trip to the emergency room when the car is running on fumes and a stop at a gas station is needed in order to get there.
Running low can cause damage, allowing the pump to over heat, getting gunk from the bottom of the tank mixed with the new fuel and possibly clogging the fuel filter etc.
Getting fuel a little more often will not cost a penny.
Hi Joseph:
I’d like to respectfully ask these two questions:
Doesn’t a pump’s cooling and lubrication come primarily from fuel flowing through it? (Far more than any cooling benefit from being submerged?)
The pump’s pickup screen is stationary, near the bottom of the tank. How does a low fuel level allow it to pickup gunk that it wouldn’t otherwise pickup?
I think lots of cooling comes from being immersed. The flow rate is pretty low, but the volume of gas in the tank is huge by comparison. Regardless, running a tank low is exactly the wrong thing to do. There are many car problems that start out “I ran out of gas, but now that I filled it up the car won’t start (or runs poorly).”
Even if he doesn’t kill the pump and doesn’t run out of gas, he’s increasing his chances that he’ll get stuck without access to a gas station. This just happened to me on Tuesday. Driving up the the freeway after a long trip, figure I had enough gas to get to the station near my house. What I didn’t know was that a semi flipped over 2 miles in front of me, shutting down the freeway. It took an extra hour to get out of that mess, with the gas gauge dropping uncomfortably low. And shutting off the car wasn’t an option, it was 112F at the time!
So he’s skating on thin ice, at some point he’ll fall in…
I’d like to respectfully ask these two questions: You have been very respectful.
Doesn’t a pump’s cooling and lubrication come primarily from fuel flowing through it? (Far more than any cooling benefit from being submerged?): Good question. I have never thought about that.
The pump’s pickup screen is stationary, near the bottom of the tank. How does a low fuel level allow it to pickup gunk that it wouldn’t otherwise pickup?: When a tank is low the fuel can slosh around and mix gunk from the bottom of the tank up to the pick up.
I agree that 10 gallon of fuel will keep a fuel pump cooler than 3 gallons. But I think the difference would be a small amount. Most fuel pumps that I have removed in the last 15 years are inside a module/reservoir. The returned fuel from the pressure regulator keeps the reservoir full. I haven’t seen any gunk in the tanks, I don’t work on Studebakers.
When a tank is low the fuel can slosh around and mix gunk from the bottom
of the tank up to the pick up.
OK, but if that is true, how would it be different than the gunk that will be sloshing around the pickup screen when the tank is more full? Is the point that, with a low tank, the concentration of gunk would be greater such that it will now plug the pickup?
My belief is the pickup screen is always subject to the tank’s debris sloshing around it. The concentration of the debris may be higher when low on fuel, but that increased concentration shouldn’t trigger a problem that wasn’t happening before.
I’m open to new data that would change my opinion.
I see the situation a bit differently–as a non-automotive issue.
If–as I assume–the OP’s husband is of at least average intelligence, non-psychotic, and blessed with normal hearing, then he is obviously aware of the multiple, reasonable requests that his wife is making (or perhaps, pleading) and he is choosing to ignore/defy her.
In essence–I believe that this stand-off may represent one or more issues:
The first possibility is a “control issue”.
(You can tell me what is logical, reasonable, and correct, but you can’t MAKE me do it.)
Secondly, he may be one of those people who enjoys constantly “living on the edge”.
An innate desire for risk-taking is related to addictive behaviors in many cases.