Deeireland:
Deisel is great when doing an oil change.drain the old oil then put bung back in and mix deisel with a little oil and put it in the engine where the oil goes and let it tick over for a while very good for for cleaning the engine out and repeat if necessary ,then add new oil
Breaks down all the gunge.
I’d be very wary of doing this, yes it will break down the gunge, but if you don’t get it all out it will continue breaking down the new oil and will ■■■■ up your bearings 
The simplest and safest way of a flush in my opinion is every now and then to use a mineral or cheaper semi synthetic oil and change it regularly (2-3000 miles) then after the second change drain and refill with the ‘good ■■■■’ 
Better then using all the cleaners and it will do just as good a job just takes abut longer
“Forte Diesel Conditioner” it’s expensive but worked a treat in my old diesel Vauxhall at MOT time!,but modern high pressure common rail diesels are normaly very clean emisions wise & don’t require additives
Yes it is better to get most of it out if not all ,but if the mix is right it does work well ,think cement! 2 diesel, 1 oil for the flush.
newmercman:
Retired Old ■■■■:
Can’t honestly see why you would need a lubricating additive in a diesel engine- after all, the fuel is OIL anyway. Or am I missing something?You’re missing the facts
Diesel is not oil, it is a processed from crude oil, but it is refined into a SPIRIT and will actually break down oil.
Tar is oil in it’s most basic form and a drop of diesel will disolve tar.
Dave, apart from the Lucas upper cylinder cleaner, I have no recommendations, except that if the system is that clogged, maybe it needs new parts
Oh dear, newmercman, I’m sorry to pour cold water on your oil refining lesson, but I fear your memory of the process seems to have got a bit skewed over the years.
Please allow an old ■■■■ to try and remind you of the simpler parts of the technique:
The normal, or “old-fashioned” way of producing fuel, whether petrol (spirit) or diesel (derv, gas oil, heating oil,whatever) is by a process known as Fractional Distillation. No magic, alchemy or fancy chemistry involved with this, despite what the fuel companies would like us to believe. All that happens is that the crude oil is heated (BIG kettle!) until the different elements of the raw product are separated by the length of their carbon atom chains.
Petrol,aka petroleum spirit or motor spirit, has between five and nine carbon atoms, while diesel has twelve or more carbon atoms. By a process of heatingand distillation, the two products are separated out according to their atomic structure. Other products, tar, naptha & other gases, lubricating oils, etc, are collected by a similar process, depending on the length of their carbon chains.
The more advanced way of doing things is by a process known by the glorious term, Chemical Conversion Processing. This allows petrol to be refined from diesel (NOT the other way around, newmercman) by chemically altering the length of the carbon chains by use of a catalyst. This is handy when the demand for petrol is greatest and is at least partially responsible for the high price of derv when compared to some years ago.
Diesel fuel is able to clean oil-bound muck simply by virtue of being thinner than the oil or grease it’s being used on but it’s still “oily” and therefore capable of lubrication, albeit, of course, not as well as thicker oils (don’t start a lecture on “viscosity” or even I will nod off).
Hope this makes things a bit clearer.
What bearings would it # up
mains and big ends for a start!
Or for a really, really clean engine and an even more spectacular #up, try running it on Jizer!
What you say about diesel is indeed correct Mr ■■■■, it is still an oil, as you say, it is a by product of the refining process that eventually produces petroleum, it is also referred to as fuel oil, to futher underline that fact, but the refining process makes it more like a spirit in terms of its lubricating properties, so it has no place in the crankcase as it will break down the heavier lubricating oils, I didn’t go too much into the specifics of Carbon Chains and that as I would’ve nodded off myself as I typed it out 
Is that better 
Viscosity, now there’s another story One interesting thing about viscosity, especially when talking about low viscosity, is the term Synthetic Oil, synthetic is usually used a dscription of something man made, yet Synthetic Oil is refined from Crude Oil in the same way as Mineral Oil, the process is just a little bit more complicated, yet the raw product is still the same, the boffins have somehow managed to get the Carbon Chains all lined up nicely so that instead of a tangled mess of components, the synthetic molecules are lined up nice and neatly, this is what gives it a lighter film strength (lower viscosity) and yet still offer better lubricating properties…yawn
An engine doesn’t need to be really ,really ,really clean but a good flush does help,and deisel helps with that flush.
Retired Old ■■■■:
Or for a really, really clean engine and an even more spectacular #up, try running it on Jizer!
I’ve got a drum of Trichloroethylene in the garage, now that’ll shift the gunge!! I think I’ll service me old F16 & run it for a couple of hrs on that to give it a proper flush. 
I wonder it it’ll work in the gearbox too?
Ross.
Just stick your head over the drum and breathe deeply, you won’t give a toss about engines or gearboxes, you’ll be too busy watching the Dragons and little green men
What you really need on a weekend is a nice neat chain of synthetic molecules!
And a gallon of Jizer.
And a sumpfull of derv.
And poor old Dave only wanted to know about fuel additives.
Retired Old ■■■■:
What you really need on a weekend is a nice neat chain of synthetic molecules!
And a gallon of Jizer.
And a sumpfull of derv.
And poor old Dave only wanted to know about fuel additives.
Completely disagree with that, what you need on a weekend is to be as far away from a lorry as is possible
newmercman:
Retired Old ■■■■:
What you really need on a weekend is a nice neat chain of synthetic molecules!
And a gallon of Jizer.
And a sumpfull of derv.
And poor old Dave only wanted to know about fuel additives.Completely disagree with that, what you need on a weekend is to be as far away from a lorry as is possible :lol:
lol. Got to give you that one, newmercman!
This is the stuff used where i work (loosemores) , very good stuff by all accounts
morrislubricantsonline.co.uk … sp?sku=MDD
cheers mike
if you feel like you need to use an additive there must be a reason , i would say just get the injectors taken out and ultrasonic cleaned and get a new fuel filter job done for another 100-200k
al_P:
if you feel like you need to use an additive there must be a reason , i would say just get the injectors taken out and ultrasonic cleaned and get a new fuel filter job done for another 100-200k
but doesnt the likes of that stannadyne stuff clean them up anyway?
bigr250:
Retired Old ■■■■:
Or for a really, really clean engine and an even more spectacular #up, try running it on Jizer!I’ve got a drum of Trichloroethylene in the garage, now that’ll shift the gunge!! I think I’ll service me old F16 & run it for a couple of hrs on that to give it a proper flush.
Ross.
is trichloroethylene what was also known as pyrene ■■