Used engine oil, put it in the tank - just wondering :)

[simonfraser]

Not very environmentally friendly I know.

But diesels can run on the oil in the sump, not for long, i know.
So i will shortly have 11 L of used lubrication, my diesel tank is 380 L, bit like making a two stroke mix.

What is likely to happen, no i wont try it !!

 

[kashurst]

hypothetically it will burn but its full of microscopic carbon and carp that could screw up your fuel injection pump and injectors. Arguably not much difference environment wise as a lot of old engine oil gets burnt anyway

 

[Baddox]

Unlike 2-stroke oil, not all of the engine oil will burn. Some of the additives designed to prolong engine life will have the opposite effect if added to the fuel in bulk.
Old-school low pressure diesel engines would be less sensitive to this than the modern, high pressure, common rail systems.

 

[superheat6k]

...
Old-school low pressure diesel engines would be less sensitive to this than the modern, high pressure, common rail systems.

It would never ever go in my 'old school' engine's fuel tanks !

 

[rafiki_]

It would never ever go in my 'old school' engine's fuel tanks !

+1. Crazy thing to do. Yes, if a diesel is getting a lot of blow by through worn rings/liners, then it can run on engine oil, but this is a totalled engine, not one you want to trust your life in at sea!

 

[longjohnsilver]

I believe that many Nordhavns do exactly that, they have a pump that introduces old engine oil to the diesel as an oil change takes place. Maybe someone can confirm this. I will ask a good friend of mine who had a Nordhavn 62 and is now cruising in the Med on his N47

 

[Momac]

Doesn't sound like a good thing to do .
Anything that even slightly risks faulty running or damage to the engine or the fuel system seems to me best avoided.
What benefit would it have?

 

[Firefly625]

well sounds a great thing to do in a hundred year time when diesel is rationed and up to £100 a litre.

Up to that point... why?

 

[Phildorset]

it's an interesting question & not ridiculous, but I'd need to know that first I'd filtered out all those little suspended particles that prompted me to change the oil in the first place, and then there's the question of whether any of the additives have a detrimental affect on my injectors etc... I won't be trying it on my own precious motors though that's for sure.

 

[No Regrets]

Recycling used engine oil isn't a new thing, but you need to do it properly, and you can't unless you can refine and heat treat it.