I have just had me Audi A4 2.0 diesel in for its first long life service at 18000 and when I checked the oil the next day it was black. I rang the dealership and they said it was normal and it was the carbon deposits. Surely these would have been removed when the old oil was changed. Is this normal for a diesel and is it ok ?
Freefall
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forgot to put in header
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I think that it is generally accepted that fresh oil put into a diesel engine (especially one on long service intervals) will go black pretty much straightaway.
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Dont worry ! ANY diesel will make its oil black after a few miles, it is the nature of the beast. There is so much carbon in suspension in a diesel engines oil, that only about a thimblefull left in the engine would make the new oil almost black before you even start driving, and I'd say that 10 miles would be enough to lose all of the translucency of the new oil.
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A number of things turn the oil black. Oil breakdown products...this occurs over a period of time and the longer the oil change interval, the worse this will get. These deposits will collect around low pressure points within the oil pathway. Metal oxides...The simply occur due to the oxidation of the metals used in the construction of the engine. Metal oxides take n a range of colours, but black is a common one. Hose breakdown products...Black rubber hoses will shed particles. They just do.
It doesn't take many black particles to turn oil black. Any body who has ever had their log fire chimney swept will know that a small amount of soot can go a long way.
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It's much better for the muck to be held in suspension in the oil than settling out and blocking oilways!
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I have just had to replace the sump on a 2003 Skoda Octavia with the PrePD engine (only difference the head and injectors I think) which had been on extended servicing at 20k and 31k. When the sump failed I put 4.5 L of new oil in to get it the 30m to the garage safely.
When I drained that out it was incredibly black, like I get from my Pug at 6k changes. I had only run for 2 minutes at most.
When I took the sump off, however, I was amazed how much black material was lining the sump sides and base when I washed it off with paraffin prior to welding despite the "oil flush" I had just given it.
Could be "normal" for this engine, or a sign that the dealer did not change the oil at 31k as he put in the book!!
Interestingly, the Haynes manual for this old engine refers to the original intervals being 6k and extended 10k or to the long life built in system. I will be going for 6k as this engine only needs SF or better grade oil, not the high-shear stuff of the PD
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While it is true that diesels dirty their oil very quickly, I would certainly not expect new oil to turn black in 24 hours unless an enormous mileage was covered. There are degrees of blackness after all.
Really knackered oil is very black indeed, and feels thin and gritty between the fingers. New oil may look dirty but will still be transparent and have some of its original colour, and will of course feel like oil.
'Long service intervals'.... carp idea.
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Common occurance with diesel engines.
www.honestjohn.co.uk/forum/post/index.htm?t=43599
www.honestjohn.co.uk/forum/post/index.htm?t=42087
Probably more - I only did a quick forum search, putting "oil" "black" in the subject box.
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" was amazed how much black material was lining the sump sides and base"
I wonder if this is typical of extended service intervals?
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My Passat PD130 is on 10K intervals, and I always check the oil level after the 2 mile drive back to my office from the dealer after a service.
The oil is **always** black
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None of mine goes black that quick. For the first thousand miles or so they both have pretty much the original new oil colour.
I change their oil every 5000 miles and always leave them to drain for a couple of hours in the garage so maybe its this what makes the difference.
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Quite wemyss. Leaving the oil in four times as long as you should and then having most of it sucked out through the dipstick hole to save service department time (but is the saving passed on to the punter we ask shrilly?) seems to guarantee lots of nasty black stuff left in the engine.
'Long life oil' has to be a bad idea. The oil may last a long time but black stuff which is probably abrasive continues to build up in it. As I remarked above, long or extended service intervals seem a bad idea, if only for this reason. And not draining the oil in the traditional manner likewise. It may be profitable to dealers and garages but it can't be good for cars.
Institutionalised slovenliness.
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I assume that the particles are too small to be filtered out by the oil filter?
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My Passat PD100 is also on 10K intervals, and the oil is **always** black shortly afterwards.
Wife's petrol Mazda 323F had brown oil shortly after its last cheap service. A quick check lead me to the conclusion that the previously trustworthy mechanic had not done the service as per the invoice. He is very old and poorly so we will need to go elsewhere in future.
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I wasna fu but just had plenty.
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All diesels I have owned, the oil has turned black as soon as the engine runs, despite changing every 4000 miles or so with top quality oil and filter. I think it's just so inky black.
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"And not draining the oil in the traditional manner likewise. It may be profitable to dealers and garages but it can't be good for cars."
I use a suction device and it *rapidly* empties a hot sump full of oil. You can hear it sucking on the bottom of the sump as it gets the last dregs out, tellingly if I then remove the sump plug nothing at all comes out.
It seems to me that a long service interval has led to oil forming *hard* sludge on the OP`s sump interior ( and I bet engine) surfaces.
There was a thread on a BMW forum recently and nothing would shift the sludge but using a scraper.
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"and nothing would shift the sludge but using a scraper.
But if it needs a scraper it's not going to be the cause of the new oil going black is it?
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106 diesel and A4 TDI turned black within 5 miles of a change of oil and filter.
Yaris diesel takes 3,000 miles.. yes really...
Note when I change oil I remove oil filter and let old oil drain for 10 mins then refill new filter with fresh oil.. so it may be the Yaris drains better from the oil galleries..
madf
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"But if it needs a scraper it's not going to be the cause of the new oil going black is it?"
Sorry Cliff, ( and others) I meant to refer to `crinkly Daves` post about hard sludge on the interior walls of his sump... Not the OP`s post about oil blackening......
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Interesting article on sludge
www.schleeter.com/oil-sludge.htm
Auto rx is available in UK which may help clean an engine, basically a lanolin ester.
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Scroll down for pics of ARX seeming to do very little for this sludged BMW.
www.bimmerfest.com/forums/showthread.php?t=94785&p...4
Mind you, it looks like a bad case......................
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