Thread: Flat Bed Truck

PhD is a postgrad qualification in any field... The core requirement is an element of original/novel thinking... AKA philosophy... I'll take the Dr Chemists' word for it over the Dr Spin's word, thanks all the same!

A Dr of Philosophy or a stand up Philosopher

Originally Posted by Celtoid

I'm a Chemical Scientist and I say you're wrong....LOL....no I'm not. Isn't a PhD a Dr of Philosophy? ....what's that got to do with diesel?

I'm not defending LR...****ed off with the issues I've had but isn't it well documented that Australian Diesel is not great (compared to Euro standards) and of inconsistant quality, especially in the Outback and with smaller operators. Can't Tank conditions also affect the fuel?

Is this all AULRO BS....hehehe.......again?

In the context of academic degrees, the term "philosophy" does not refer solely to the field of philosophy, but is used in a broader sense in accordance with its original Greek meaning, which is "love of wisdom".

A doctorate in engineering / chemistry / physics is still a PhD in 99.9% of Australian Unis.

Diesel in AU is not as bad as some make out. Diesel must conform to the fuel quality standard - which is basically the same as in EU, etc...
Fuel Quality in Australia - Diesel fuel quality standard
Heavy penalties for non conforming diesel.

We have had ultra low sulphur diesel for many years.

All diesel sold in AU comes from a small number of sources, so there should be little variation unless some dodgy people are doing their own blending.

Some diesel sold in AU has higher aromatics than others. Aromatics are generally undesirable in diesel (they increase octane but not cetane rating). Aromatics make rubber seals swell up. When BP (Brisbane) introduced diesel with lower aromatics (i.e. better diesel with higher cetane rating) in the mid/late 90's in AU, there were a lot of older seals which failed. However even the oldest D3 should not be old enough to have issues of a similar nature.

Thanks for the clarification guys...on both PhD and diesel.

Sounds like diesel issues in Aus are an urban myth then.....just like LRs being unreliable....

Originally Posted by Celtoid

Thanks for the clarification guys...on both PhD and diesel.

Sounds like diesel issues in Aus are an urban myth then.....just like LRs being unreliable....

Don't get me wrong there is dodgy diesel in AU, however usually because it has been contaminated with dirt/water/microbes - or blended by some dodgy servo or distributor - between the refinery/port and point of sale.

I know some refineries in the past have shipped in cheap, high sulphur diesel from china, etc - however they have to blend it to make sure it (just) meets the AU fuel standard before sale.

Originally Posted by isuzurover

Don't get me wrong there is dodgy diesel in AU, however usually because it has been contaminated with dirt/water/microbes - or blended by some dodgy servo or distributor - between the refinery/port and point of sale.

I know some refineries in the past have shipped in cheap, high sulphur diesel from china, etc - however they have to blend it to make sure it (just) meets the AU fuel standard before sale.

So, like Ben says the fuel and its effect on seals aren't the issue, it is more than likely a fitting problem.... years ago when I first started servicing D3's I fitted a fuel filter to one that came with some pretty good instructions on how to avoid damaging the Orings when fitting the new filter...back then I thought obviously there has been some problems with fitting/ leaks etc, enough for LR to include literature in the box with the filter.


JC

Fuel quality may have played a part but not a primary one.

from the "WVO and anything else I can find thats free, oil like and burns" experience with the tdi300

Normally when replacing the fuel system filter I lube the seal then just spin it on till it contacts and then give it a little more, its by no means tight but its not so loose that it can twist loose. Occasionally after changing drums of fuel from one batch to another when refilling a couple of days after the refill SWMBO will complain of a fuel like smell in the car and sure enough the filter will be dripping but still in the same physical location (I usually write the date+ks on the filter after installation so its easily seen). This means seal failure of one nature or another but I'm yet to encounter it where giving the filter an extra part (usually 1/4) turn fails to sort it.

My theory on this is that something in the previous batch of fuel has expanded the seal and that something in the second has caused it to contract or vice versa and the creeping of the seal has been enough to ripple it so it doesnt make full contact. The saving grace of the tdi fuel system is that the filter is in a low pressure part of the system so the seal isnt trying to hold back much.

In a common rail (or unit injected in some cases) with the filter in a full pressure/high flow environment thats not the case its operating at full supply pressure to the high pressure pump and often at much higher flow rates than in an older style diesel. The seal is now holding back a lot more and a very small leak very quickly becomes a major one and the seal gets damaged.

I suspect that some servos may not be dispensing the same quality of fuel and lets just say for a second that high sulfur diesel will cause the seal to shrink and that a 10% bio blend will cause it to expand. IF you had filled up with the bio mix and run it the seal will expand, extrude where it needed to and then begin to settle into that shape. If you then ran the high sulfur mix it would then contract in the same shape which then causes a leak.

Is the fuel the root cause? no, in my experience it's the sealing surface and the seal are not adequately cleaned and lubricated prior to installation or the filter not being done up tight enough to compress the seal adequately (its a statoic o-ring style seal so a compression of 10-20% of the seals width is appropriate)

Is the filter not being on properly the only cause? No, usually something else adds the straw that breaks the camels back in some cases its mechanical vibration, in others its the fuel changing the conditioning of the seal.

D3/4/RRS diesel fuel filter is after the low pressure pump and before the HPF pump. I do not know of any filters after the HP pump.