Diesel engine oil black in 2 days?...........

[1TUFFUTE]

Um my friend got his small diesel car serviced and had an issue under the bonnet....so while i checked that for him i checked his engine oil......jet black and it was supposed to have been serviced with oil and filter change only 2 days before. IS THIS Normal. Apparently he rang back and it is....and a dealer he rang said the same thing basically. But 2 days does NOT sound right to me.
Any info would be appreciated....taa

[GASWAGON]

Some diesel engines have a 'bypass' filter that should also be changed when normal filter is changed....The bypass filter holds a small amount of oil and it contributes to making the new oil dirty again if not changed....What sort of car is it? Does it have a bypass filter fitted?

[1TUFFUTE]

It's an 2007 focus 2.0ltr diesel turbo. 90k service. But was 3 k over due.

[mac_man_luke]

Could be sludge that was built up from the overdue service. Could be worth doing another oil and filter change.

Diesels do blacken quick but 2 days is pretty quick.

[Jason[98.EL]]

check this thread out on piston heads

sound like it is normal for it to do it

I just googled

why is oil black in a diesel

there is plenty of info there

hope that helps

Jason

[martinijosh]

Sounds like they either forgot to change the oil but still invoiced or forgot to change the filter.

[dleach80]

It's a diesel it's gonna turn black very quickly, you can never drain the entire amount of oil resulting in old oil sitting in the sump, head, galleries unless you let it drain over night, all there interested in getting your car in and out as quickly as possible.

[Rodge]

Originally Posted by dleach80

It's a diesel it's gonna turn black very quickly, you can never drain the entire amount of oil resulting in old oil sitting in the sump, head, galleries unless you let it drain over night, all there interested in getting your car in and out as quickly as possible.

Yeap that's pretty much it. Because it was ovrdue for a service it would have been jet black and the oil ramaining in the engine after allowing it to drain out affects the new oil going in. They blacken up the oil pretty quick, its just how diesel engines are, they don't call them dirty engines for nothing...

The oil in my SC GT-P looks cleaner after 8,000 km's and 12 months than my Euro diesel does after driving it around the block from the dealer after its service.

[TC200six]

As others have said, black oil in diesel engines is normal.

It's impossible to clean out the engine's internals from changing the oil & filter alone and the new oil gets contaminated with what's left of the old oil. As long as you know the oil and filter was changed, you have nothing to worry about.

[1TUFFUTE]

Originally Posted by Jason[98.EL]

check this thread out on piston heads

sound like it is normal for it to do it

I just googled there is plenty of info there

hope that helps

Jason

Thanks that sorts it out....apparently they go black before you get home......weird and goes against everything I'd expect but its safe and true.
Thanks

[ILLaViTaR]

If it's black it's burnt/contaminated and it will cause damage/wear. How is this safe to use over the next 10 000k's?

If it's normal every single motor will have the same problem, and I bet some don't have black oil.

[1TUFFUTE]

Originally Posted by ILLaViTaR

If it's black it's burnt/contaminated and it will cause damage/wear. How is this safe to use over the next 10 000k's?

If it's normal every single motor will have the same problem, and I bet some don't have black oil.

that's exactly what I thought and instantly told my friend....."oil goes black from heat and getting burnt over time...plus contaminated"
But apparently in diesel motors its 100% normal because the oil carries particulates or some garbage aswell as lubricating. All sounds stupid to me.....espescially when diesel engines don't rev high hence far less heat....so wheres all the gunk and burning coming from? Ahwell....he inquired...was assured it was re[laced and any engine damage is covered under warsnty by the diesel engine oil companies....weird hey

[TC200six]

To the above two comments. This is why I believe diesels should have their oil changed much sooner than 15,000ks. But it seems all companies have extended their intervals to that.

Oils in diesel engines contaminate differently due to the different fuel. You see, oil of LPG engines contaminate yellow, petrol motors contaminate brown or black if running rich.

If the Focus uses a cartridge filter, I would say to change the filter before draining the oil, because the filter holds a bit of oil itself, and if you remove the filter after refitting the sump plug, some old oil will run down into the sump. Hope that makes sense.

[302 XC]

Originally Posted by 1TUFFUTE

that's exactly what I thought and instantly told my friend....."oil goes black from heat and getting burnt over time...plus contaminated"
But apparently in diesel motors its 100% normal because the oil carries particulates or some garbage aswell as lubricating. All sounds stupid to me.....espescially when diesel engines don't rev high hence far less heat....so wheres all the gunk and burning coming from?

Diesels don't need to rev high to generate heat,they run comp ratios twice,sometimes 3 times that of a petrol engine, then throw some turbo boost in there, and your talking temps hot enuf to melt pistons, and they don't need to rev to do it ...
I know of some older diesels running over 20 : 1 ratio and get fed over 15 + PSI of boost,and don't rev past 4,000 rpm ....

[chookaradley]

You say it was black within 2 days. More often than not they are black within 2 minutes. I've serviced heaps of diesels of all makes and models and found this to be the case. I don't think the colour of the oil nesessarily detracts from the oils ability to protect your engine(in a diesel). I've had more than one occasion where a customer has complained about not having there oil changed when I had done it.

[irish2]

Originally Posted by 1TUFFUTE

that's exactly what I thought and instantly told my friend....."oil goes black from heat and getting burnt over time...plus contaminated"
But apparently in diesel motors its 100% normal because the oil carries particulates or some garbage aswell as lubricating. All sounds stupid to me.....espescially when diesel engines don't rev high hence far less heat....so wheres all the gunk and burning coming from? Ahwell....he inquired...was assured it was re[laced and any engine damage is covered under warsnty by the diesel engine oil companies....weird hey

20:1 comp ratio produces more heat than a quick rev in a petrol...

[GTP-RPD]

Yep drive a work diesel captiva and oil goes black within half an hour of driving after an oil change. Perfectly normal I have been told. Seen the new oil go in.

[GASWAGON]

You cannot stop a bit of discolouration from changing the oil.....The new oil will be 100% fine for 10-15,000k's, but after that it HAS to be changed.....I've just had a friend tell me he hasn't serviced his crummydore on gas for 3 yrs.... If thers one thing to do on a car its CHANGE THE BLOODY ENGINE OIL!

[SumoDog68]

Originally Posted by EF_6

You cannot stop a bit of discolouration from changing the oil.....The new oil will be 100% fine for 10-15,000k's, but after that it HAS to be changed.....I've just had a friend tell me he hasn't serviced his crummydore on gas for 3 yrs.... If thers one thing to do on a car its CHANGE THE BLOODY ENGINE OIL!

Technology is changing some commonly held concepts - it is possible to have oil do its job for much more than 10-15k.

[martinijosh]

Originally Posted by EF_6

You cannot stop a bit of discolouration from changing the oil.....The new oil will be 100% fine for 10-15,000k's, but after that it HAS to be changed.....I've just had a friend tell me he hasn't serviced his crummydore on gas for 3 yrs.... If thers one thing to do on a car its CHANGE THE BLOODY ENGINE OIL!

Same thing, guy I know with a vz sv6 hasn't changed the oil for 40,000

[ebxr8240]

Diesel oil contains much higher detergent percentage .. Although oil is black the engine is clean !!
Make sure the air cleaners are in good nick or it will run rich...
Short trips on diesels require more frequent servicing..

[Legit290]

Yeah I used to have a diesel work ute. It freaked me out when I had the oil and filters changed and checked the oil when i got it home and it was black. My mechanic laughed when I hassled him about it.
Perfectly normal

[Yellow_Festiva]

Search for my thread in the Focus section. My oil was black again leaving the dealer after a service.

Normal apparently.

[Yellow_Festiva]

Originally Posted by SumoDog68

Technology is changing some commonly held concepts - it is possible to have oil do its job for much more than 10-15k.

I was close to buying a Punto diesel very cheap so downloaded the manual for UK spec cars and I think oil intervals were something crazy like 30k between changes.

My Focus gets done every 7.5km.

[nb_351]

The black is carbon and of a Diesels engine oil is clean it's not doing it's job, blank and runny is perfectly normal even after long intervals
Carbon is a by product of a diesel combustion motor
The trucks I service at work go 30000km between changes, that's the Detroit motors, caterpillar and cummins I do at 20000km intervals
45L still gets mighty dirty after that time but the technology these days in oil is much better than even a decade ago, some truck manufacturers specify 40000km with the correct oil but I think that is too long

[b2tf]

If the oil isn't dirty I would be worried. Oils job is to remove contaminants from the engine (along with everything else it does) - it should be coming out looking filthy.

[burnz]

Originally Posted by ebxr8240

Diesel oil contains much higher detergent percentage .. Although oil is black the engine is clean !!
Make sure the air cleaners are in good nick or it will run rich...
Short trips on diesels require more frequent servicing..

nailed it.

and diesels actually run lean, fuel is added with a full open intake. (no throttle body)

[martinijosh]

Originally Posted by Yellow_Festiva

I was close to buying a Punto diesel very cheap so downloaded the manual for UK spec cars and I think oil intervals were something crazy like 30k between changes.

My Focus gets done every 7.5km.

That's once every trip to the supermarket. :p