Old Diesel

[CharlesA]

Can diesel go off? I have some in a jerry can that came with my boat and is at least 4 years old and could be a lot older. Is it safe to use? If not, what's the best way of disposing of it? Any expert feedback on this much appreciated. Thanks.

 

[vyv_cox]

The low molecular weight content of diesel fuel is much lower than that of petrol. There is far less likelihood of loss of properties by ageing, especially in a closed container. My diesel VW camper is laid up in UK and has had the same fuel in the tank for 6 years. It starts first turn of the key when tested about once or twice per year.

If you still have doubts, decant a small amount of it into your fuel tank each time you top up with fresh fuel.

 

[Guest]

OK lets put this one to bed ..... Diesel, or more correctly termed Gas Oil .... (Diesel is the name after the guy who designed an engine to use it !) .... has little aromatics and VP compared to gasolines and other spirits.
Vaporisation of 'light-ends' is the biggest problem with any fuel and diesel is lucky in this respect that due to the engine using extremely high compression to fire the fuel, instead of a piddly spark, the fuel will normally burn with only a very slight decrease in performamnce that you and I will not notice.

The only time really that diesel will not burn well is after a) extreme cold having passed through its Cloud Pt / Cold Filter Plugging Pt temps. Then you have a small amount of precipitation remaining after warm up. This occurs in normal red diesel at about -5 to -10 C, in city diesel ref. Spec EN590 UK .... at about -15 C ... b) when having been subjected to extreme heat and precipitating Gum ... which will likely not re-disolve and then you should be acreful not to up-end the can.

HONESTLY ...... if worried mix with new 50/50, other wise just chuck in a bit now and then using it up with good stock. ME - I would just throw it in and use it, as I can tell by smell / colour likely characteristics .... very unprofessional, but owning / operating a PetroChemical Inspection Lab does help !

 

[KeithH]

I agree with Nigel's comments. Use diesel up by dilution with newer fuel is sound advice. This diesel stability issue is actually improving with the advent of low sulphur diesel. That low S diesel (often called City Diesel in the UK) is severely hydrotreated in the refinery to remove sulphur, a process which also removes a lot of the unstable components which lead to gum formation. So the newer diesel fuel should be more storage- stable than the older material.

These comments only apply to diesel - petrol or gasoline has different storage stability issues - loss of light ends (which leads to poor starting) and gum formation due to polymerisation of the olefinic species, being the main ones.

KeithH

 

[Johnjo]

Have being reading this post with interesr,
Noting the differences between gas oil and City diesol,
Much of which go's over my head.
Would I be right in assuming that City diesol would have a bit more pep to it?
And being a cleaner fuel, If that's the right word,
Increase the power output of the engine,resulting in less black smoke on higher revs or acceloration,
mike

 

[vyv_cox]

Unfortunately not. Calorific value is unchanged, so no more output. Black smoke little different because that is partially burned hydrocarbons, and so not affected. Lower sulphur in the fuel reduces or eliminates emissions of sulphur oxides and acids, contributing to acid rain and other environmental problems.

Its downside is that the sulphur lubricates many components of the engine and there are currently several automotive manufacturers experiencing problems that may be caused by these fuels. Exhaust valves are probably top of the list.

 

[dickh]

Nigel, as you are an expert in fuels, is gas oil as used in home heating fuel the same as red diesel as used on boats/farms? If so, can heating fuel be used on my boat? Is this legal and would anyone find out if it wasn't... Heating fuel is certainly much cheaper than red diesel - 20p as aginst 30p/litre approx. Not that it would make a huge difference to my boat fuel bills as I only have a small engine in a sailing boat.
I'm sure many people would be interested in your answer.

Also can heating oil be used in my diesel car without harm(Peugeot 2.0 HDi) - although I know this is illegal as it says so on the heating oil invoice - not that I would dream of using heating oil and depriving the Exchequer of fuel tax!

dickh
I'd rather be sailing...

 

[Guest]

City Diesel / Gas oil

Cuty Diesel is Gasoil, but Gas Oil is not City Diesel ....

City Diesel is EN590 stock that has Sulphur content below 50 ppm

Gas oil is correct name for Diesel

Diesel is like using the name Hoover for a Vacuum Cleaner.

As to extra pep - the short answer is = NO

 

[Guest]

Lubricity coeeficient is a requirement of all diesels in EU now and a coefficient of 450 nanomtrs is the test spec. Lubricity additive is a regular addition to ULSD and eliminates this problem. Except where cheaper additive is used that is unstable after a few weeks.
Most fuel stock is months old by the time it hits your pumps and this may explain some poor results when tests are made on pump delivered ULSD against original batch tests at Refinery / storage where additive is put in.

The specs for lubricity are possibly going to be tightened soon and of course cost will be apssed to Joe Blogs in the street.

 

[Guest]

Some bright spark ... forgive the pun - is now going to ask about Olefins ..... this is where I call a halt !!!!