Cannot b less than half tank?

[Obscurest]

Folks,

 

just wana check wif u guys that is it true that is not advisable to wait till empty then we top up petrol.

 

Reason being the tank will oxidized n rust will form n in the end clog up n will ve to send engine for overhaul.

 

Sounds logical but Im not quite convinced as in the manufacturer shld know about tis n a better material shld b used for the fuel tank.

 

Can someone kind to clear my doubts?

 

Becos of tis issue, my friend who drive a cng car worries as he only keep 1/4 tank of petrol as standby when cng runs low.

 

He will try to clear the old petrol only once a mth and pump in new petrol n maintain 1/4 tank as standby again.

 

Basically he works and stay near a cng station thus he hardly uses petrol.

 

Another question is that is it alright for him to do in this way?

 

Thks.

[SimonTan]

Depends on whether the tank is make of what material.

Also depends on how often you pump petrol.

Also depends on how often you want to change your car and fuel filter.

 

Many theory, no correct answer.

 

Best is just pump whatever it makes your feel good.

Some change engine oil often.

Some don't dare to rev their engine.

Some used only 98ron fuel.

In the end, the depreciation of the car is still the same when it comes to selling it away.

 

[Mockngbrd]

not true...

[SimonTan]

Ok my honest reply.

The fuel tank is mostly flat.

So even if you only maintain 10% of petrol all the time. The movement of the car, will slosh the petrol inside the tank while you drive. It will coat the tank internal surface all the time. Petrol will not cause rust, its the water moisture that will cause the rust. And that happens mostly if the car is not driven for a long time, like winter period!

 

Also many tanks are made of composite plastic, that will not rust at all.

 

[Obscurest]

So generally it depends on the material of the tank?

 

Hhhhmmmm.....

 

That's really diff....

 

As for me, I pump to full tank once a week. Is that consider as long?

 

My friend who is driving a Toyota noah I think so... Is a mpv. He only pump 1/4 tank once a mth ONLY!!!

 

Guess that's not advisable rite?

 

He still do his reg servicing on time. Is tha ok?

[Little_prince]

no true at all lah

[Assaxefour]

I remember Tay Pin hui did a TVC for shell and he said do not wait till empty tank to topup to prevent rust!

[SimonTan]

Petrol floats or sink, compare to water?

If you check density of petrol it is less than 1.

So it means if there is water in your fuel tank, the water will be at the bottom. Pump full tank or 10%, the water will still be at the bottom, right?

 

Go and figure it out yourself.

Of course if we want to talk about rusting action, we are going to talk about metal tank without internal rustproofing, or with damaged internal coating. Unless you dented the tank thru accidents, I don't see how rusting should be a concern for modern cars.

[Obscurest]

Petrol floats or sink, compare to water?

If you check density of petrol it is less than 1.

So it means if there is water in your fuel tank, the water will be at the bottom. Pump full tank or 10%, the water will still be at the bottom, right?

 

Go and figure it out yourself.

Of course if we want to talk about rusting action, we are going to talk about metal tank without internal rustproofing, or with damaged internal coating. Unless you dented the tank thru accidents, I don't see how rusting should be a concern for modern cars.

 

 

Noted...

 

Then if forever maintain at 1/4 tank, any issue?

[Lowrider]

empty fuel tank can cause;

 

- dirt in the bottom of the tank can be sucked up and clog the fuel lines

- air in tank has a certain water vapor which in turn can cause condensation

- petrol is lighter than water, so water from condensation will settle in the bottom thus can cause rust

- petrol doubles as cooler for fuel pump, if it's empty the pump can get too hot thus premature failure

 

Well, those are the theories...

 

 

[Obscurest]

So is not advisable to maintain at 1/4 tank.

 

Will share with my friend to keep full tank even if He is using cng.

 

His reason is since he is using cng most of the time, he don't wana drive around with full load of petrol.

 

Hhhmmmmm wat a pity.

[Zyrofillica]

i think shd be more concerned about the fuel pump. i think may car designs the fuel pump is submerged in the petrol which helps cool it. so maybe if too little petrol in tank, pump is not submerged, hence may overheat?

Edited October 18, 2010 by Zyrofillica

[Ben5266]

empty fuel tank can cause;

 

- dirt in the bottom of the tank can be sucked up and clog the fuel lines

- air in tank has a certain water vapor which in turn can cause condensation

- petrol is lighter than water, so water from condensation will settle in the bottom thus can cause rust

- petrol doubles as cooler for fuel pump, if it's empty the pump can get too hot thus premature failure

 

Well, those are the theories...

Another theory to add.

More air room in the tank, more petrol will evaporate. ==>wasted

[Obscurest]

Ok

 

thks for all the help n advices

 

think will tell him to keep at least 3/4 tank.

 

Thk u so much.

[Good-Carbuyer]

Folks,

 

just wana check wif u guys that is it true that is not advisable to wait till empty then we top up petrol.

 

Reason being the tank will oxidized n rust will form n in the end clog up n will ve to send engine for overhaul.

 

Sounds logical but Im not quite convinced as in the manufacturer shld know about tis n a better material shld b used for the fuel tank.

 

Can someone kind to clear my doubts?

 

Becos of tis issue, my friend who drive a cng car worries as he only keep 1/4 tank of petrol as standby when cng runs low.

 

He will try to clear the old petrol only once a mth and pump in new petrol n maintain 1/4 tank as standby again.

 

Basically he works and stay near a cng station thus he hardly uses petrol.

 

Another question is that is it alright for him to do in this way?

 

Thks.

Can share with us who gave that reason? First time I read such reason?

 

[Good-Carbuyer]

I remember Tay Pin hui did a TVC for shell and he said do not wait till empty tank to topup to prevent rust!

Is he a vehicle Mechanic or Shell petrol salesman?

[Zyrofillica]

Ok

 

thks for all the help n advices

 

think will tell him to keep at least 3/4 tank.

 

Thk u so much.

 

3/4 tank?

thats too much la. machiam ride 2 stroke bike, every 2 days have to go top up petrol ah? I think keep to above 1/4 is more than enough.

[Altivo]

If driving car, the tank won't rust cos they are made up of plastic high-density polyethylene (HDPE).