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Fuel pump , transsmison

was wondering about two questions? first one, i read in a book, that if you are waiting for a train at a crossing for a long period of a time, its better if you place your car in neatural. because if it sets in drive and you keep your foot on the break, the transmisson has strain on it and it gets hot. is this a true story. i dont know how many people really do , do this to there cars. but i have been doing that as soon as i was told this. my second question, i was told also fuel cools the fuel pump, and it is not good for the fuel pump, if your are the person who lets your car freqently go out of gas.and that your not suppose to let your car get to low because particles of the gas tank can harm the pump or the system. is this also true? thanks

If you’re going to be waiting for a train for a long time, yes, you should shift to neutral or park. There’s not enough strain on the transmission to make it overheat, but why sit there with your foot on the brake? Put it in Park and wait for the train to pass.

I also suggest shutting off the engine to save gas while you’re waiting.

Yes, the fuel pump is inside the gas tank, and is cooled by the gasoline. If you constantly drive around without much gas in the tank it can cause excess wear on the pump. I suggest never letting the tank get below 1/4 full.

Allowing the car to run completely out of gas is very bad for the entire fuel system. You should never allow this to happen under any circumstances.

I agree that when waiting for an extended spell you should cut the car off or at least shift into neutral.

Also agreed that you should not allow the tank to run empty. The fuel does cool the pump (a good thing) but it also serves another purpose. The fuel acts a lubricant because the pump is full of gasoline when running.
Fuel injection pumps turn very high RPMs and once the pump starts sucking air any gasoline residue will burn off in a nano-second and wear will occur on the pump bushings or bearings.

A good rule of thumb is that if you are going to be sitting idle for more than a minute or two, you might as well park it and shut it down. Idling is just a waste of gas, and the urban legend about a car using a tremendous amount of fuel to start and much less to idle is pure fiction. The transmission could really care less, unless it’s a manual and you’re using the clutch as a ‘hill holder.’

It is true that you should keep at least a quarter tank of gas in your car to prolong the life of the fuel pump, and also so you don’t run out of gas and get stranded. Running out of gas is very bad for the engine and catalytic converter. If you’ve ever heard the knocking sound of a newer car running out of gas, that is preignition caused by a very lean condition resulting from fuel starvation. Preignition can and will cause severe engine damage and very quickly overheat and melt down the catalytic converter.

Another interesting thought on keeping gas in a car is that the sending unit can actually wear out. I once replaced the sending unit in a Dodge pickup to correct an intermittent gauge accuracy problem. The owner had a tendency to “five dollar” the gas tank all the time, as in, he would run it to empty, put five dollars in it, etc. He actually wore the rheostat on the sending unit down to nothing between empty and a quarter tank!

If the “train wait” is not a regular event shutting the cat off is fine. If for some reason you regularly have waits beyond one minute and shot the engine off regularly, you’ll exposte the starter motor assembly to additional wear and could promote premature failure.

I keep my fuel tank usually above 1/2 and always above 1/4 for safety. In 1971 when I got stationed in North Dakota, before cell phones were even science fiction, we attended a training course for cold weather survival. It included tips on staying alive when not on duty. One was to always to keep at least 1/2 tank of gas and how to conserve that fuel. If you broke down on the highway in ND in those days it could be days before someone found you, and the temperature could be -20F days and -40F nights. Without a source of shelter and heat you could die. People actually did. A few died every winter.

I’ve kept that 1/2 tank habit with me ever since.