Colour of oil AFTER oil change (diesel)

[qooqiiu]

Just had my van serviced by a main dealer and checked the air, pollen,& fuel filter...they have been changed.

But, when i look at the oil on the dipstick its just as black as before the service. When i query this the service guy says its normal for it to be black so soon after changing coz there's always small deposits of old oil in the engine that get mixed up with the new stuff after a short road test.

bks or OK?

[kambites]

In my experience it only takes a few minutes of running to turn a diesel's oil black. I only have experience of old diesels, though.

Edited by kambites on Wednesday 9th June 17:30

[Richard-G]

ok, oil in modern diesels carrys particulates, it would have been jet black on its second or third pass thru the engine, within minutes

[the_lone_wolf]

Just to echo the above comments

In my experience Diesel oil will go black as soot before you get the car home from the service

Nothing to worry about

[anonymous-user]

My diesel is only two years old and has always been serviced on time with decent fully synthetic oil, it goes black almost instantaneously and I too have been told it's pretty normal.

[nelly1]

To get 'clean' oil you have to:-

Change oil & filter
Start engine
Drain oil & refill
Start engine
Drain oil & refill
Start engine
Top up oil

I know this because that's what we have to do after a 50 hour dyno COP (Conformity Of Performance) test before the engine is returned to the production line.

[anonymous-user]

nelly1 said:

To get 'clean' oil you have to:-

Change oil & filter
Start engine
Drain oil & refill
Start engine
Drain oil & refill
Start engine
Top up oil

I know this because that's what we have to do after a 50 hour dyno COP (Conformity Of Performance) test before the engine is returned to the production line.

Or buy a Petrol

[nelly1]

That would also work...

[qooqiiu]

Thanks for putting my mind at rest gents.

I also just jacked it up and there's a oily wipe mark around the sump / plug so that's made me less suspicious too.

[Colin 1985]

Why are there so many partials in diesels? I have only had petrols in the past so fresh oil means exactly that, nice clean new oil when dipped. I must say this surprises me I would have thought a diesel engine should be roughly the same as a petrol engine?

[Eggman]

Colin 1985 said:

Why are there so many partials in diesels?

I've never really thought about it before, but would assume it's for exactly the same reason that soot and filth comes pouring out of the exhaust - it'll be all the products of combustion you get with diesel oil. Since the combustion happens in the cylinders, I suppose some gets dragged down the cylinder walls by the pistons and ends up in the oil.

(I made all that up off the top of my head, btw. Someone will no doubt be along to tell us what a load of old cobblers it is! )

[Colin 1985]

Eggman said:

Colin 1985 said:

Why are there so many partials in diesels?

I've never really thought about it before, but would assume it's for exactly the same reason that soot and filth comes pouring out of the exhaust - it'll be all the products of combustion you get with diesel oil. Since the combustion happens in the cylinders, I suppose some gets dragged down the cylinder walls by the pistons and ends up in the oil.

(I made all that up off the top of my head, btw. Someone will no doubt be along to tell us what a load of old cobblers it is! )

That did occur, but still if so much is left in would have though it might make sense to flush the system with cheap oil or something similar.

[Fartgalen]

My old 98 Escort TD would go probably a 1000 miles or so before the oil was black again.

[dylan0451]

i assumed it's the silly high compression ratios diesels run at compared with petrols - there's always going to be some blowby/contamination

also, isn't this why you're not supposed to put diesel oil of the same rating into a petrol - the level of detergents is much higher to ensure the engine doesn't get baked, caked in it's own deposits but that they're held in suspension of the oil, hence it goes black so fast?

on a k series i had, ok it was a petrol but i changed the oil + filter so often that after a while i didn't have to so much - the engine was throughly cleaned out and the oil remained a golden barley colour for much longer

Edited by dylan0451 on Wednesday 9th June 20:21

[dave_s13]

I cleaned out the EGR plenum chamber on my V70 D5 recently.

Looked like this

Before


After


That's 103k miles worth of $hitted up exhasut gas being recirculated round the engine.

Makes you wonder how the damn things keep running.

I posted a thread about it on a V70 forum.
http://www.volvoforums.org.uk/showthread.php?t=941...

[dylan0451]

fk me gently, that is the biggest oil/soot buildup i've ever seen!

was it starting to run rough or was only xfactor on the telly?!

[dave_s13]

dylan0451 said:

fk me gently, that is the biggest oil/soot buildup i've ever seen!

was it starting to run rough or was only xfactor on the telly?!

It was running absolutely fine. Oh and I noticed no difference after getting rid of all the gunge??

It had an issue with the turbo inlet pipe collapsing under pressure that was throwing up an error when using the kickdown. In my quest to find this out (using the above linked beardy forum) I learnt these engines can benefit from a check of this pipe.

So I checked it while I had my spanners out....and fck me!!

[dylan0451]

well then, from that beardy forum i'd take advice from the chap and blank it off. i'd doubt the combustion chanbers are anything like that since thats the st they're kicking out. if it passes mot that way, and you stay fault code'less it can't be bad