Myth Or Fact?

[geno8r]

Myth or Fact?

Sediment collection from running fuel tank too low?

I think I've read about this subject before but here we go again. I came to the conclusion that it was a myth, as for Fuel is drawn from the bottom of the tank so having a low tank wouldn't make any difference to a full tank, BUT, I've just come across a quote from the Nissan website & now it's got me unsure again!

http://www.nissan.com.au/owningNissan/vehi...enance.asp#fuel

  Quote

Also, avoid running the tank too close to 'Empty'. Petrol impurities and sediments collect at the bottom of your tank and can cause problems if drawn into the fuel line.

Can someone please clear this up & technically explain why it's myth or fact? If it wasn't for me reading that Nissan page I would have still thought it was a Myth.

[Modena]

Yep thats what it says in the manual. Also mechanics will tell you the same.

[Munkyb0y]

my theory is that when the tank is full, the sediment, or crud as i call it, is more diluted around the tank. but when the tank is low, the crud is more concentrated so its more likely to get drawn inot the line.

remember......i said 'theory'

[geno8r]

  CCCP said:

Yep thats what it says in the manual. Also mechanics will tell you the same.

I'm looking for a little more than just “Nissan & Mechanics say so”, I like to know how things work so if somebody can technically explain why it's a fact that'd be great, thanks

Edited January 3, 2007 by geno8r

[d0p3y]

yeah bingo not good for your fuel pump especially i've had a few friends who run their tanks to the very last drop constantly and as such have had fuel pumps die early......

i do on occasion run it until the fuel light is on unintentionally but most of the time ensure the tank is as full as possible.......

think about it --- say you're drinking a drink using a straw, do you really like scrambling for the last drops from the bottom of the glass, or do you prefer drinking from a full glass? the fuel pump would feel the same about trying to feed your engine its fuel

[Eug]

only one way to find out...

any special way to flush the fuel tank?

- remove tank plug

- bucket

- jerry can

- rinse repeat?

[geno8r]

  d0p3y said:

yeah bingo not good for your fuel pump especially i've had a few friends who run their tanks to the very last drop constantly and as such have had fuel pumps die early......

i do on occasion run it until the fuel light is on unintentionally but most of the time ensure the tank is as full as possible.......

think about it --- say you're drinking a drink using a straw, do you really like scrambling for the last drops from the bottom of the glass, or do you prefer drinking from a full glass? the fuel pump would feel the same about trying to feed your engine its fuel

Makes sense, but not really a direct answer to my question, more a related answer *but thanks for the knowledge anyway *.

Getting back to the actual sediment issue.

  Munkyb0y said:

my theory is that when the tank is full, the sediment, or crud as i call it, is more diluted around the tank. but when the tank is low, the crud is more concentrated so its more likely to get drawn inot the line.

remember......i said 'theory'

Sure, but over time I guess it's all going to get sucked through the injectors anyway seeing fuel is drawn from the bottom right?

[Modena]

  geno8r said:

I'm looking for a little more than just “Nissan & Mechanics say so”, I like to know how things work so if somebody can technically explain why it's a fact that'd be great, thanks

Ok, your fuel pump runs hotter (less lubrication cos not much fuel there). Your fuel injectors will get clogged up with all the petrol tank gunk. Thats the two main worries.

[Haysey]

well the bottom of the tank on my 13year old car is pretty damn spotless so i reckon youd have to be using some shit petrol for a long time to get any collection of sediment on the bottom...

[predator]

In both my skylines that have been over 10 years old, the tank has been crystal clear whenever I've gone to change the fuel pump.

I think it's a bit of a myth in most cases, but that said, there ere are probably a few out there that have had dodgy fuel put into them in some Japanese country area or something, and hence crap gets in there. So the only real way is open up your tank, shove a torch in and have a look for yourself.

[Sumo]

  predator said:

So the only real way is open up your tank, and light a smoke

Couldn't have said it better myself

[gts-4 dreamer]

nissan might recommend not running a tank empty due to overheating in fuel pumps, less fuel pumps fail early less get replaced on warranty, i doubt its sedimentation and more the overheating fuel pump failing

my couple of cents eh

[PHATR32]

when i pulled the fuel tank out of my car (89 model) it was clean, no crap at all.

unless someone in japland cleaned it, i think this mainly a myth, OR counts only for older cars with steel gas tanks. i suppose..........

[Richmond98]

Maybe its to avoid air in the fuel lines.

[Mr Italy!]

  CCCP said:

Your fuel injectors will get clogged up with all the petrol tank gunk. Thats the two main worries.

So why do you have a fuel filter in your engine bay? To sit there and look shiny... no, it filters the fuel before it gets anywhere near your injectors.

[Modena]

  Mr Italy! said:

So why do you have a fuel filter in your engine bay? To sit there and look shiny... no, it filters the fuel before it gets anywhere near your injectors.

Do you realise that you can clog up your petrol filter way before the 15000 KMs intervals its meant to changed?

[Mr Italy!]

  CCCP said:

Do you realise that you can clog up your petrol filter way before the 15000 KMs intervals its meant to changed?

Obviously, its a filter so its gonna clog up, so change it before the 15000KMs interval if you think its gonna clog up sooner. Its still a filter that sits between your tank and your injectors...

[Modena]

  Mr Italy! said:

Obviously, its a filter so its gonna clog up, so change it before the 15000KMs interval if you think its gonna clog up sooner. Its still a filter that sits between your tank and your injectors...

Yeah but with that approach your car's not gonna last very long. If you wonna run your petrol tank dry and change fuel pumps and fuel filters every 5 000 Kms then go for it

[Mr Italy!]

  CCCP said:

Yeah but with that approach your car's not gonna last very long. If you wonna run your petrol tank dry and change fuel pumps and fuel filters every 5 000 Kms then go for it

Exactly my point.

So we agree that its a myth?

[Guilt-Toy]

Just dont use a lighter =)

  predator said:

In both my skylines that have been over 10 years old, the tank has been crystal clear whenever I've gone to change the fuel pump.

I think it's a bit of a myth in most cases, but that said, there ere are probably a few out there that have had dodgy fuel put into them in some Japanese country area or something, and hence crap gets in there. So the only real way is open up your tank, shove a torch in and have a look for yourself.