darker diesel

bikedaft

bikedaft

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had 3-4 (25litres) lots of fairly dark diesel from one place now.

have spoken to them, they are going to take it up with their supplier (bilsand fuels)

but will it cause any damage to engine?

runs fine, idle and load. (wth darker fuel)

never serviced injectors in the last 4 years. filters changed twice a year, no bug etc

am going to try diesel from elsewhere, but looking at a 24hr motor around the MOK friday night as little wind :-)

thanks

(first lot was darkest, i assumed it had been contaminated with oil as seems more viscous, so ignored it)
 
Now is the right time to document what happens. Keep a tight log on things and do not delete anything.

The fact that you made an early claim might prove to be your best insurance at a later state. The thought of an oil company paying for a new engine sort of enjoys me..
Happens every now and then with cars and the suppliers are well insured to cover these incidents..

Trucking companies have to clean their bulk trailer tanks every now and then and ever so often the cleaning agent isn't completely removed before filling with fuel.. :cool:
 
Many years ago one of the things i used to do was test the gas oil fuel supplied for gas turbines ( essentially aircraft jet engines) used for electricity generation.

I seem to remember quite a variation in the depth of colour.

Provided it is "clear and bright" in appearance I would not be concerned but perhaps rather suspicious if it was obviously of a higher than normal viscosity.

I am sure we also measured the viscosity but I don't remember now what sort of variation was normal.
 
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Worth noting that some of the delivery tankers have three or four tanks on board carrying different fuels-diesel,keroscene and sometimes heavy oil which is thicker than diesel and is still found in use in commercial central heating systems-particularly oil fired schools.
According to my delivery driver if they have been offloading heavy oil they should finish by flushing with a small amount of diesel or keroscene depending on what their next delivery is.Get it wrong or dont flush the pipe and you might find some heavy oil contamination
 
The discoloration might be a result of the cracking process. For reasons that are beyond my knowledge aluminium oxide is sometimes added to the crude oil and that can cause problems. Have come across discoloured kero when I was working on product tankers. As somebody posted, keep records and keep samples. Aluminium oxide is highly abrasive.
 
I once had trouble running all my plant & it turned out that the "cheep" supplier was re refining old fuel & oil etc
Not sure what the process is but every one of my diesel engines started playing up
Perhaps the process is better now but it could well be still being used & you may be getting re processed fuel
If it os heating oil it will run the engine ok ( i have done it) but you could be at the end of a VAT fiddle if s company is mixing the fuel with road fuel . Not saying you are, but it could be done
As a hedge against Any future problems keep a sample & show sample to Office of fair trading. They would love it
 
Thanks for all your replies.

Dredging memory, and switch receipts, 3 lots of 25 litres of diesel

Nos 1 and 3 were from a different bowser, and were darker. No 2 was a more normal colour.

Not imagining it - the water trap bowl colour is fair bit darker.

Have got some of the 3rd lot, will keep it, thanks.

Suspect it is fine as engine runs fine. Will tell you on sat night if we make it to tayvallich :-)

Tho hope there is no Al oxide...
 
bikedaft said:
Thanks for all your replies.

Dredging memory, and switch receipts, 3 lots of 25 litres of diesel

Nos 1 and 3 were from a different bowser, and were darker. No 2 was a more normal colour.

Not imagining it - the water trap bowl colour is fair bit darker.

Have got some of the 3rd lot, will keep it, thanks.

Suspect it is fine as engine runs fine. Will tell you on sat night if we make it to tayvallich :-)

Tho hope there is no Al oxide...
Click to expand...


Maybe some Marine Diesel MDO has got into the system. This can be quite dark. Not sure how modern all singing wee diesels with lots of elektrickery would cope but an old Volvo or Yanmar should cope though the exhaust might not be as clear as before.
 
From what I read, I think dark fuel = fuel that has degraded for one reason or another, whether that is in your tank or somewhere upstream. Ours certainly looked dull and lifeless.

This makes interesting reading http://mydieseldoctor.com/FAQ.html as does the rest of the website.

I've just spent 3 months in Greece burning off 270 litres of dark fuel, and pumping a pint or two of bug/sludge from the bottom of the tank.
During that time I must have 'polished' the tank contents 3-4 times using an electric pump and spare CAV filter assembly.
Normally I keep the tank brimmed, but no amount of new fuel would lighten the colour so I decided to run it through and disposed of the last 40 litres or so.
Cant say that I noticed any smoke or drop in performance, though its a 25 year old MD30 that we rarely need to push hard.

One thing I did learn, if you put a bit of bug/sludge in a jar and add a dose of new clean fuel and agitate it, the new fuel quickly takes on a darker colour that does not settle out.

I have also decided to buck conventional wisdom of keeping the tank full for our 8-9 month storage ashore, as it seems modern diesel is not as stable as before, so I run it near dry at the end of our season, dose whats left with marine 16 and start afresh next year after sucking out any water and contamination I can get at.

Steve
 
geoffatstanpit said:
Aluminium oxide is white so wouldn't colour the fuel. Unless it's crushed rubies and emeralds?!
Click to expand...

If adding Al Ox was the whole story your observation would no doubt be correct.
My post was based on experience on product tankers where discoloured diesel cargoes had been a problem. Not being a chemist I can not provide chapter and verse of the process but in simple terms it goes something like this; In order to get more light product ( automotive diesel and lighter) Al Ox was added to the crude. Some other chemicals where also added in conjunction with the Al Ox. Because of some mistake in the dosing the fuel came out dark and when exposed to sunlight went darker still.
If memory serves me right about 24,000T were rejected.
 
well, got round the mull of Kintyre

just.

motored most of way until lighthouse, then good sail for 5 miles north. fog off the mull, not pleasant, went along inside passage. cleared out to the west.

engine failed at machrihanish beach. air in fuel line. of course I thought it was dirty clogged filters at first, but changed them, and still leaking air in

so off to change the fuel line, and (embarrassingly old rusty) shut off valve that is now leaking diesel to the engine. hopefully its not the fuel take off from tank weld.

we made it in the end. tried rigging up a temp fuel line from top of tank. worked, but I had flattened the batteries (another story!)

got a tow from bottom loch sween (thanks, venture west rib). no wind.

mmm plenty lessons learned;

isolate engine starter battery :-)

turn off nav lights during daytime :-)

always carry spare jerrycan fuel

fix things before they break, especially if you have to get back to work Monday...

thanks for all the replies.
 
Just out of interest what container is it in? Colour wise, I've often thought my diesel was dark but when I take out a glass and look at it, I find its ok
 
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This is how mine looked, compared to new fuel.
 
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