Will Running Out Of Gas Damage Your Car?

[Daox]

I'm not sure how many of you have seen this channel, Engineer Explained but I really enjoy it being an engineer myself. He goes through several scenarios and explains pretty well how running out of fuel will effect your vehicle.

[Basic]

I'm an engineer, and I think everything he said is overkill...

That said, I grew up on a farm and have seen lots of things work that a classically trained "engineer" would immediately dismiss and say NO to...

I bet you could run a Mirage out of gas every month you owned it and never have a problem.

[inuvik]

I don't know if running out of fuel will damage the longevity of your Mirage but I DO know that running out of fuel will damage your timeliness to arrive at your destination

[dspace9]

I'm an engineer, and I think everything he said is overkill...

That said, I grew up on a farm and have seen lots of things work that a classically trained "engineer" would immediately dismiss and say NO to...

I bet you could run a Mirage out of gas every month you owned it and never have a problem.

I ran out gas back in 2003 I believe, in a 1985 VW Rabbit. 0 harm to the car. I know things can happen but even once a month nothing will happen, I believe it. No point in doing that exercise, of course.

[Cobrajet]

I'm an engineer, and I think everything he said is overkill...

That said, I grew up on a farm and have seen lots of things work that a classically trained "engineer" would immediately dismiss and say NO to...

I bet you could run a Mirage out of gas every month you owned it and never have a problem.

I have run my Mirage out of gas at least a dozen times, likely more. I almost always run it down to the last fraction of a gallon before filling it back up, and I always fill it up. I think I have only put a partial tank of gas in my car once or twice. Run it to empty or near empty...fill it all the way back up.

No problems to report.

[Cobrajet]

I'm an engineer, and I think everything he said is overkill...

That said, I grew up on a farm and have seen lots of things work that a classically trained "engineer" would immediately dismiss and say NO to...

I bet you could run a Mirage out of gas every month you owned it and never have a problem.

The video is about nine minutes long, and the short answer is, "No, unless you are Loren."

When your fuel pump starts sucking air you lose fuel pressure. When you lose fuel pressure your engine sputters to a stop within about a minute...ask me how I know. Is there horrendous damage being done between the time you lose fuel pressure and the time your engine stops? Nope.

[Loren]

The video is about nine minutes long, and the short answer is, "No, unless you are Loren."

Hey!

The theory (which can be expressed in about 1/20th of 9 minutes) is that even just running extremely low on fuel can cause your fuel pump to run hot and shorten its life. If you've got 2+ gallons of fuel in the tank, it acts as a heat sink for the fuel pump. As you get down to that last half gallon, the temperature of that remaining fuel can rise. Fuel pumps have plastic frictiony parts inside that don't like heat.

I agree, once you start sucking air, fuel stops flowing, engine sputters and stalls. Though not necessarily "instantly".

Anecdote: I have no working fuel gauge in my S10. It has a 16 gallon tank, and DRINKS fuel. I need to fill up every 180-200 miles. And sometimes I forget to reset the trip meter until I'm a few miles away from filling up. And sometimes I drive harder. And sometimes I take a lot of short trips.

Long story short, I learned recently that the truck will simply run like CRAP for quite a while before it actually runs out of fuel and completely stalls. I think this was mentioned in the video (which I tried to watch, but ended up just skimming through the first 5 minutes of). Fuel slosh.

The last couple gallons in the truck (which will last me about 28 miles... which when I'm doing 5 mile trips once per week just to "exercise" the truck... is actually a long time!) will slosh and uncover the fuel pickup. So, if I accelerate hard, I get fuel starvation and a bog. If I stop hard for a stop sign, I get fuel starvation and it stumbles or stalls as I come to a stop. Once I'm stopped, it will restart just fine!

So, that whole period of several weeks where I was putting up with that, but not realizing that I was just low on fuel... wasn't exactly healthy for my fuel pump.

Bottom line: Yeah, you're not really going to hurt anything other than your pride by running out of fuel every now and then. But, don't make it a habit of running around on fumes all the time.

[Cobrajet]

Hey!

The theory (which can be expressed in about 1/20th of 9 minutes) is that even just running extremely low on fuel can cause your fuel pump to run hot and shorten its life. If you've got 2+ gallons of fuel in the tank, it acts as a heat sink for the fuel pump. As you get down to that last half gallon, the temperature of that remaining fuel can rise. Fuel pumps have plastic frictiony parts inside that don't like heat.

I agree, once you start sucking air, fuel stops flowing, engine sputters and stalls. Though not necessarily "instantly".

Yes, I understand the 'theory'. I just don't see how a small, 12v DC electric motor generates enough heat to essentially destroy itself by running without 'coolant' for minutes or even hours.

I mean, the coolant-less 12v blower motor in the dash doesn't generate a bunch of self-detonating heat, does it?

[Eggman]

I mean, the coolant-less 12v blower motor in the dash doesn't generate a bunch of self-detonating heat, does it?

That blower motor gets cooled by the airflow it provides and it might not have to work as hard as a fuel pump that has to produce however many pounds of fuel pressure in a small package.

[Loren]

Blower motor probably has bearings in it, and it is cooled with an endless supply of air. Fuel pump has a spindle turning in a nylon bushing... lubricated by gasoline.

Like I said, just running out of fuel every now and then isn't going to hurt anything. CONSTANTLY driving around very low on fuel... there is potential.

The other thing a "dry" fuel pump does is spin VERY, VERY fast. It's used to having a load on it. Remove the load with the same power applied... I don't have numbers, but it does spin a lot faster.