Surely diesel is very changeable depending on temperature. .

Modern day diesel is relatively unaffected by temperature, in the old days it used to "wax" as the temperature fell but nowadays additives included in the diesel ensure this is unlikely at least in this country.

In hotter weather it expands more, colder weather it is more compact.

Ok, (puts nerdy hat on) this is true in principle, BUT the co-efficient of expansion of diesel is such that even taking it to ludicrous extremes with say a sudden 100C rise in ambient temperature, that's a 100C rise which would mean that it would be so hot that all life on the planet would cease to exist ! :eek:

With a full tank of diesel and even with this huge rise in temperature the amount of diesel actually expanded would not so much as fill an egg cup ! Assuming you did actually manage to expand an egg cup full even this would not be sufficient to cause any problems at all as the plastic tank in the Fabia would expand enough to cope with that !

That is why I would never fill my overflow tank on a hot day.

Back in the real world ..... you are perfectly safe to do so Emily, it's a fallacy to worry about diesel expansion in hot weather ever causing you any problems whatsoever so far as filling your tank to the brim is concerned.

Now with petrol that's a totally different story ! :eek:

(removes nerdy hat)

Deleted, double post.

Back in the real world ..... you are perfectly safe to do so Emily, it's a fallacy to worry about diesel expansion in hot weather ever causing you any problems whatsoever so far as filling your tank to the brim is concerned.

Now with petrol that's a totally different story ! :eek:

(removes nerdy hat)

Thanks for putting it all straight in my head. These are all conclusions i have drawn from hearing about diesel on here and talking to other people.

I have a very botched knowledge of the whole process, clearly. My excuse is that I have a D in GCSE physics.

TBH I am very stuck in my ways so even though I know about the egg cup thing, I still will not fill my reserve on hot days.

Just filled up at the tesco pump (only about a few litres of diesel left because of all the panic buying ) and added the millers stuff. See what happens.

I'm a Shell Diesel Extra man myself for 3 reasons.........

1. I noticed no real difference when compared to BP Ultimate

2. I have a V Power card as that's all that ever goes in the CTR so i get points when i fill up with Diesel Extra.

3. It's a heck of a lot cheaper than Ultimate!!!!! (I'm a Yorkshireman don't forget:eek: )

I get a bit of clag when i boot it but that's just a design thing with the VAG engine.

I too am glad i have seen DevonUtopia's post above........ Absolute classic and cheered me up on my 12 hour day shift :rofl: :rofl:

Cheers

Dave.

Just filled up at the tesco pump (only about a few litres of diesel left because of all the panic buying ) and added the millers stuff. See what happens.

The Millers says on the bottle it will take 250 miles before you see any effects from it so you probably won't see immediate changes

Chris

Oh dear.... Sobering up now and can't be assed to edit

Regarding diesel expansion, if you're interested, have a read at Basil's thread, here

My economy has really gone down too. Interestingly, I always get better economy on the way back from work than the way to work. Yet, I take the same roads and it's not as if work is at the top of a mountain and I live in a valley... I put it down to the fact I'm town driving then a motorway burst whilst the car is still cold.

But even a 22 mile cross-country commute with 10 miles at a constant 50mph still doesn't get me much above 43-45 mpg. I can reach 50mpg on the drive home.

I do have a tank of BPU, and I don't think it's making that much difference. Whether I should fill it up a second time to give more adaptation time, I don't know, but I'm tempted to try the millers additive at some point (never have before). Whether it improves economy as well as performance though, I don't know. Any ideas?

I do have a tank of BPU, and I don't think it's making that much difference. Whether I should fill it up a second time to give more adaptation time, I don't know, but I'm tempted to try the millers additive at some point (never have before). Whether it improves economy as well as performance though, I don't know. Any ideas?

I've never noticed any difference with Ultimate, even running a few tanks through. I'm currently running through some Millers Diesel Power Sport and my economy is 5mpg higher than normal (may be a coincidence!) but I'll see how it goes as I'll be doing a couple of miles over the next few days

Chris

The Millers says on the bottle it will take 250 miles before you see any effects from it so you probably won't see immediate changes

400 miles so far.

I think I am starting to see it.

Emily, as the Ibiza has the same engine in, would you recommend this stuff? Even though Skoda and Seat say not to add additives into fuel?

Miller Oils Diesel Powerplus is brill - been using it for years. Given the same 'foot-heaviness' you do get better economy. However, the tendency is to use the extra oomph.

Used it for 180k on my old Cavalier diesel, passed every yearly emissions test with absolute flying colours. Tester was suitably impressed each time. Mechanic tried it a few years ago and has been using it ever since.

Whenever I ran out of the stuff I could immediately tell - the car felt so sluggish. Even my wife could tell - she used to ask me if the Millers was in or not.

I reckon for the difference to be so noticeable the car must have been pushing out an extra 10% power.

The quieter running, the extra power you notice within a few miles. The cleaner injectors etc is probably the 400 mile mark mentioned by some.

And no, I'm not called Emily, just couldn't resist jumping in.

Emily, as the Ibiza has the same engine in, would you recommend this stuff? Even though Skoda and Seat say not to add additives into fuel?

Yeah I would.

I have no idea how much it costs as I was given it as a gift.

I would say give it a go for certain.

I *might* try the combination on millers and heating oil as I can get it for A LOT less per litre.

I have noticed the same in mine mate Just a change in varriables from summer to winter, I am now get 49mpg instead of 54mpg in my everyday driving.... still better then the 30mpg - 34mpg I was getting with my old felly I would relax and wait for the better times of summer

Q

An redcution of 40 Watts on a car whose engine produces 95,000 Watts - wouldn't worry about it!

Yor engine won't be producing 95kW most of the time, so the proportion is much more, and that 40W had to come from somewhere...

I had noticed, what seemed to be, a significant drop in efficiency through the cold mornings... thought that driving more carefully (I keep to the speed limits, but allow the car to reach them as quickly as possible!!) that would help... NOPE... it just seemed to make it worse... I even reached a 'trip computer' low of 26mpg after a cold day at work... quite depressing really, when compared to the 50mpg average over a tank (not taking into account 'trip computer' variances (lies) and the post's on manually working out mpg)... and the 62mpg (yep from the 'trip computer' M5 from Plymouth to Bath trip of the summer...