Shaking Vehicle while filling petrol - will it help?

pjbiju · 11th July 2007, 14:20

I think it is an unnecessary act. It is always safe to stop at the auto-cut off mark. Also all the fuel tanks have some mechanism, either built into the cap or as an extra fitting to let air in/out. So if air can go in/out, then fuel too can seep out if filled to the brim.

ankit.jhamb · 11th July 2007, 15:02

even my santro`s fuel tank can adjust 3 to 4 lts of fuel on shaking...bt logically ..the volume of fuel tank is same ...so how can we get extra fuel by shaking the car ....

Thad E Ginathom · 11th July 2007, 15:35

What's the point?

I know some people who never ever drive with a full tank except when they are going on a long trip.

They fill up often, and with just a little --- like 1/4 tank or something.

The idea is simple: A full tank adds to the weight of the car: why use fuel to carry the weight of all that fuel around?

I have always been too lazy to even think about doing such a thing, but it seems many members here consider fuel consumption very important, and, I guess, every little counts!

Also, although I'm convinced it is psychological, I have this feeling that a car with a full tank runs better!

msdivy · 11th July 2007, 15:47

My car's tank is 42 litres. When I fill till auto cut-off, its usually 38 litres. I know there still some fuel in it. If I shake, I can fill at most 1/2 litre more. Not worth the effort.

I guess people do it so that they fill maximum quantity of fuel in the tank and thereby reduce the number of trips to the bunk.

dadu · 11th July 2007, 15:56

there is always a small spillover pipe attached to the cars fuel inlet hose, which connects back into the tank. if you fill 1/4th tank you also let the fuel evaporate more in the empty space.

the auto-cut is no benchmark for a full tank and will always fill lesser than a full tank due to the mechanism, when the fuel comes back to the hose, it puts pressure on the filler hoses tip and that activates the cut off. since the fuel is whirling inside the tank, its usually earlier than the actual full tank.

shaking can give you max 0.5 to 1ltr more fill, nothing more.

DieselFan · 11th July 2007, 15:59

Quote:

Originally Posted by Thad E Ginathom

What's the point?

They fill up often, and with just a little --- like 1/4 tank or something.

Not a recommended practice. Almost empty tanks have higher evoporation of fuel hence one tends to get lower FE. It is therefore recomended to fill the tank up before it falls below 1/3 capacity.

amitoj · 11th July 2007, 16:16

Quote:

Originally Posted by DieselFan

Not a recommended practice. Almost empty tanks have higher evoporation of fuel hence one tends to get lower FE. It is therefore recomended to fill the tank up before it falls below 1/3 capacity.

Also, doesnt this practice of not filling the tank to full make it more prone to corrosion?

V-16 · 11th July 2007, 16:18

Shaking a car whilst filling fuel is probably the worst thing one can do. This is probably done to get the maximum fuel in the tank and for some it is a force of habit. But is this good? How would you feel if you had to stuff in so much food that you could not put in another morsel? Works the same way. Filling the tank to the brim will do more harm than good.
Usually the fuel delivery from the pump will snap stop after it detects that fuel has reached the filler tube. This is because the incoming fuel foams and this fools the pump head into shutting off. One may try filling in again but not by using coersive methods ashaking the car. After the second try in a short while, you will hear a second snap and the pump will again shut. One should not proceed after the pumping device shuts off for the second as some air space must be left above the fuel to allow for expansion and also for fuel to recirculate from the engine. This is essential for purposes of maintaining a constant fuel system pressure, as well as maintaining a uniform temperature throughout the fuel system.

manaa45 · 11th July 2007, 16:24

i too shake the car to release the air in the fuel tank.

it also happens sometimes that excesive air may result in the stalling or non starting of the car.

so it is better to shake the car while filling up.

Mansi

Thingummy · 11th July 2007, 16:27

Interesting thread this - i've read multiple numbers being mentioned about the quantity of fuel that can go in after the auto-cutoff, anywhere from 10-12litres (was it a truck?) to "not more than 1L max" - i am sure this is highly dependent on the vehicle type. On my zen, i could never top up more than 0.5L after auto cut-off (despite the shaking and all that), whereas on the Palio, i have regularly been able to go beyond 2L after auto cut-off (must admit the zen was a lot more easier to shake than the palio is)

snaronikar · 11th July 2007, 18:02

My car takes in about 1 ltr after auto cut off if we shake the vehicle. I do this when ever I'am filling the petrol to tank full and will be on long trip....

nitrous · 11th July 2007, 18:16

Quote:

Originally Posted by dadu

if you fill 1/4th tank you also let the fuel evaporate more in the empty space.

Do u have proof for this,dadu?

Quote:

Originally Posted by amitoj

Also, doesnt this practice of not filling the tank to full make it more prone to corrosion?

Aren't fuel tanks made of plastic,these days,amitoj??
PS: Nice to see u back on the forum.

amitoj · 11th July 2007, 18:19

Quote:

Originally Posted by nitrous

Aren't fuel tanks made of plastic,these days,amitoj??
PS: Nice to see u back on the forum.

Thanks!! And DOH

!! now i know i had heard this in relation to bikes.

Jaggu · 11th July 2007, 18:31

what was i thinking when i read the title lolz.

my thought dont shake em so much!! take a break and see if second fill happen with auto cut off, or just leave it at that. not worth the effort

nitrous · 11th July 2007, 18:37

What is the objective of the shaking??
How is it going to affect the car or FE??

11th July 2007, 14:20	#16
pjbiju Senior - BHPian Join Date: Apr 2006 Location: Pune Posts: 1,357 Thanked: 1,089 Times	I think it is an unnecessary act. It is always safe to stop at the auto-cut off mark. Also all the fuel tanks have some mechanism, either built into the cap or as an extra fitting to let air in/out. So if air can go in/out, then fuel too can seep out if filled to the brim.
	() Thanks

11th July 2007, 15:02	#17
ankit.jhamb BHPian Join Date: Jan 2007 Location: new delhi Posts: 573 Thanked: Once	even my santro`s fuel tank can adjust 3 to 4 lts of fuel on shaking...bt logically ..the volume of fuel tank is same ...so how can we get extra fuel by shaking the car ....
	() Thanks

11th July 2007, 15:35	#18
Thad E Ginathom Distinguished - BHPian Join Date: Jun 2007 Location: Chennai Posts: 10,987 Thanked: 26,340 Times	What's the point? I know some people who never ever drive with a full tank except when they are going on a long trip. They fill up often, and with just a little --- like 1/4 tank or something. The idea is simple: A full tank adds to the weight of the car: why use fuel to carry the weight of all that fuel around? I have always been too lazy to even think about doing such a thing, but it seems many members here consider fuel consumption very important, and, I guess, every little counts! Also, although I'm convinced it is psychological, I have this feeling that a car with a full tank runs better!
	() Thanks

11th July 2007, 15:47	#19
msdivy Senior - BHPian Join Date: Aug 2006 Location: Bangalore Posts: 1,815 Thanked: 2,826 Times	My car's tank is 42 litres. When I fill till auto cut-off, its usually 38 litres. I know there still some fuel in it. If I shake, I can fill at most 1/2 litre more. Not worth the effort. I guess people do it so that they fill maximum quantity of fuel in the tank and thereby reduce the number of trips to the bunk.
	() Thanks

11th July 2007, 15:56	#20
dadu Senior - BHPian Join Date: May 2007 Location: Bangalore Posts: 3,803 Thanked: 462 Times View My Garage	there is always a small spillover pipe attached to the cars fuel inlet hose, which connects back into the tank. if you fill 1/4th tank you also let the fuel evaporate more in the empty space. the auto-cut is no benchmark for a full tank and will always fill lesser than a full tank due to the mechanism, when the fuel comes back to the hose, it puts pressure on the filler hoses tip and that activates the cut off. since the fuel is whirling inside the tank, its usually earlier than the actual full tank. shaking can give you max 0.5 to 1ltr more fill, nothing more. Last edited by dadu : 11th July 2007 at 16:00.
	() Thanks

11th July 2007, 16:18	#23
V-16 Senior - BHPian Join Date: May 2005 Location: mumbai Posts: 4,594 Thanked: 950 Times View My Garage	Shaking a car whilst filling fuel is probably the worst thing one can do. This is probably done to get the maximum fuel in the tank and for some it is a force of habit. But is this good? How would you feel if you had to stuff in so much food that you could not put in another morsel? Works the same way. Filling the tank to the brim will do more harm than good. Usually the fuel delivery from the pump will snap stop after it detects that fuel has reached the filler tube. This is because the incoming fuel foams and this fools the pump head into shutting off. One may try filling in again but not by using coersive methods ashaking the car. After the second try in a short while, you will hear a second snap and the pump will again shut. One should not proceed after the pumping device shuts off for the second as some air space must be left above the fuel to allow for expansion and also for fuel to recirculate from the engine. This is essential for purposes of maintaining a constant fuel system pressure, as well as maintaining a uniform temperature throughout the fuel system. Last edited by V-16 : 11th July 2007 at 16:30. Reason: add
	() Thanks

11th July 2007, 16:24	#24
manaa45 BHPian Join Date: Dec 2004 Location: nerul, navi mum Posts: 357 Thanked: 49 Times	i too shake the car to release the air in the fuel tank. it also happens sometimes that excesive air may result in the stalling or non starting of the car. so it is better to shake the car while filling up. Mansi
	() Thanks

11th July 2007, 16:27	#25
Thingummy BHPian Join Date: May 2007 Location: Bangalore Posts: 103 Thanked: 0 Times	Interesting thread this - i've read multiple numbers being mentioned about the quantity of fuel that can go in after the auto-cutoff, anywhere from 10-12litres (was it a truck?) to "not more than 1L max" - i am sure this is highly dependent on the vehicle type. On my zen, i could never top up more than 0.5L after auto cut-off (despite the shaking and all that), whereas on the Palio, i have regularly been able to go beyond 2L after auto cut-off (must admit the zen was a lot more easier to shake than the palio is)
	() Thanks

11th July 2007, 18:02	#26
snaronikar Senior - BHPian Join Date: Jun 2007 Location: Bengaluru Posts: 2,845 Thanked: 29 Times View My Garage	My car takes in about 1 ltr after auto cut off if we shake the vehicle. I do this when ever I'am filling the petrol to tank full and will be on long trip....
	() Thanks

11th July 2007, 18:31	#29
Jaggu Team-BHP Support Join Date: May 2004 Location: Bangalore Posts: 20,212 Thanked: 15,891 Times	what was i thinking when i read the title lolz. my thought dont shake em so much!! take a break and see if second fill happen with auto cut off, or just leave it at that. not worth the effort
	() Thanks

11th July 2007, 18:37	#30
nitrous Senior - BHPian Join Date: May 2004 Location: UAE/Lon/Madras Posts: 6,965 Thanked: 325 Times View My Garage	What is the objective of the shaking?? How is it going to affect the car or FE??
	() Thanks

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