Is It Bad Practice To Let The Diesel Run Low?

emzino

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Hi all.

I usually only fill up when there's around 15miles left in the tank (DIS read out). But a friend of mine said how I shouldn't leave the tank empty like that as it causes air (?) in the tank.

I questioned it as it sounds abit daft but thought i'd ask on here just in case.

Thanks!
 
Ive read the same thing. Although i think its less of a problem on newer diesels.

Its more to do with fully running out of diesel all together, requiring your car to be deairated (not sure if thats the correct term) which is expensive.

But in general its not good practice in any car to go down to the dregs of the tank
 
Its to do with condensation building up in your tank and mixing with the diesel which is baaad.

Do I know whether this theory has any credence? no.
 
I regularly let it run down to 5 or even 0 miles before filling up. Never had a problem in 19,000 miles of driving it like that.
 
Same here, mine often gets down to 5 or 0 and I've never had a problem. Should have learnt my lesson really as I actually ran out in my previous 2.0 tdi sport & was s****ing myself that I'd done some damage but topped it up with a can and it fired up straight away...wouldn't recommend it though!!
 
Ah so it's not an actual fact, more of an urban myth heh.

Well that's ok but I think i'll create another thread regarding what happens once you have ran out!
 
I was under the impression that it it used to be because you were more likely to pull the rubbish that used to be in diesel fuel, through the fuel system. Causing problems for the fuel filter and poor running.

This was because Diesel wasn't really a clean fuel until recently, and you also couldn't guarantee that it hadn't picked something up along the journey from the refinery to your tank. The risk was that you would get 'dirtier fuel' at a the bottom of the fuel tank (sediment etc), that the car's fuel pump would pick up off the bottom of the tank and take into the system as you got very low.

However I think refining of diesel now is a lot better, and this is less and less likely to happen. With modern diesels I think the worst that would ever happen now is actually running out.

Old diesel engines also needed a lot of manual priming if you ran out. This was a hand pump in the fuel line near the engine. My Peugeot 106 Diesel used to have this. I don't beleive modern diesels have this and so I don't think this is also an issue anymore.
 
^^ basically agree

It depends on the quality of diesel in your country, but generally, it is a less "clean" fuel than others and also tends to accumulate some water through the distribution process. Bearing in mind it is being injected through micro-passages at high pressure, it's wise not to get yourself in a position where there is an increased risk of picking up contaminants.
 
true you dont want a fag butt lodgin in ya turbo diesel filthy stuff

^^ basically agree

It depends on the quality of diesel in your country, but generally, it is a less "clean" fuel than others and also tends to accumulate some water through the distribution process. Bearing in mind it is being injected through micro-passages at high pressure, it's wise not to get yourself in a position where there is an increased risk of picking up contaminants.