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Old 18th December 2006, 11:29   #1
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Default Why does engine Oil go Black immediately?

I changed my car's oil recently and about 200kms after the service I noticed that the color is black from clear oil that it was.
I talked to Tata workshop guys, they checked the oil and said its perfect and after a few kms of driving it goes black.
I did not trust them at all and asked them to show me oil's of some other cars. What I saw in 2 indica's and a safari that barely a few kms after oil change the oil is black. One of the indica's had done just 10,000 kms and had driven just 20kms after oil change!
They told me its the carbon which causes this blackness, and as long as the oil does not become thick, its okay.
Any thoughts about where does all this carbon come from. I change oil every 5-6K kms, and yet there is carbon.
The engine is running fine, good pickup, good mileage and no problem with compression etc., and is definitely not eating oil as there is no smoke too.
Moreover I doubt 3 new cars will have engine problems, so this blackness of oil is a natural phenomena. So can the experts tell me what is the source of this carbon etc.,

EDIT:
Could sulpher be the culprit
API Oil Service Categories
This gives API standards. The latest is CI-4. But all the new ones like CG, CH, CI which can be used in place of CF are for sulpher content below 0.5%. CF grade is for higher sulpher content diesels. So is it possible that using a higher grade oil like API-CG(Shell super diesel) is actually not beneficial as using CF(GTX magnetic, GTD) because CF is designed for sulpher content higher than 0.5%? I am not sure if diesel used in India is high sulpher diesel or Low sulpher diesel.

Last edited by tsk1979 : 18th December 2006 at 11:40.
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Old 18th December 2006, 14:20   #2
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I remember reading this. Oil turning black means job well done. But on many forums I found that petrol engined cars had oil retaining honey color for longer time than diesel engines. So was wondering what is this black thing apart from oxidised oil. Is the debris more in diesel engines?
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Old 18th December 2006, 14:26   #3
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is your car a diesel ? in diesels oil tends to turn black quite early, the oil changes colour as it retains or traps the oil which is oxidised and also component wear , soot etc , if its black means its retaining properties are good and oil is doing its job.

Last edited by Kinetik : 18th December 2006 at 14:40.
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Old 18th December 2006, 14:35   #4
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I feel its more to do with the carbon deposits being more in diesel engines in the compression chambers. Petrol cars produce lesser carbon soot
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Old 18th December 2006, 14:59   #5
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The Oil turns black simply due to carbon (byproduct of combussion) and dirt. A good oil filter will keep some of the dirt at bay, but the carbon buildup is inevitable.

Dont worry about it, TSK.
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Old 18th December 2006, 17:02   #6
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Exhaust emission readindgs are the key to understand whats happening inside engine...........various readings of Hydro carbon,CO,CO2,O2 and nitrous oxide indicates combustion efficiency.............now what we call as good combustion bound to produce certain amount of all gases........but in reality unburnt fuel is the main culprit for oil blackening.......when less combustion takes place or engine misfires either then HC level is increased.......If we can manage to bring down HC level then we can have good engine oil life......

Changing the fuel changes the emission........using gaseous fuel like LPG reduces emission drastically & makes oil clean after consistant use....

This is an excellent reading for exhaust analysys...

http://www.autoshop101.com/forms/h56.pdf

Enjoy......
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Old 18th December 2006, 18:32   #7
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I was told the reason oil turns black is because drops of petrol mix with oil in the combustion chamber , this is becos' the tolerance level in the gap between the rings and the chamber are not accurate, this tends to turn the oil black
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Old 20th December 2006, 12:59   #8
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i had the same problem in my accent crdi-the service engineer at kun hyundai told me its normal for diesel cars' engine oil to go black.my palio 1.6 has run nearly 7000km now without an oil change and the oil colour is still golden brown.guess its only the case with diesel cars.
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Old 20th December 2006, 14:30   #9
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I have a WagonR and have noticed this too. When i top her up with Castrol Magnatec, the oil has a honey color, but after 1000Kms, it turns brownish. In that case what is the interval one should change oil. Also this means that we cannot decide when to chanhe the oil, based on the color. I have to check the viscocity (thickness)?
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Old 20th December 2006, 14:32   #10
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Okay, so I guess nothing to worry.
One more question, what happens when you use an Oil meant for Low Sulpher diesel with high sulpher diesel(the kind available in India)?
FYI, Castrol GTD, MAK Diamond, Castrol GTX magnetic are API-CF which is the highest grade for "high sulpher diesel", whereas MAK CI4, Shell super diesel, Castrol edge, Mobil 1 are all CG/CH and higher grades which API specifies are for
"Low sulpher diesel"
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Old 20th December 2006, 15:36   #11
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Ok fellows, all my queries are now solved. Some googling and API engine oil guide solved my worries
Some information I got.
E-II engines require low sulpher diesel type II which is 0.05% i.e. 500ppm
I can use upto API-CI4 grade oil in my car since its E-II. Usage of API-CJ4(which is not available as of now) which will come in 2007 will protect my engine better, but 500ppm sulpher content will damage oil more quickly. So I have to change sooner.

India has to go to 0.0015% i.e. 15ppm for E-IV norms. That is Ultra Low sulpher diesel.
Usage of that diesel with normal engine oil will lead to additional engine wear and tear. SO better to go for CJ4 when using ULSD, which will come very late to India.

The most worrysome part for Diesel engine guys. When newer cars like Mercedes etc. come into India confirming to international standards, they will have DPF(Diesel Particulate Filters) in the exaust systems. These systems will suffer low life due to no ULSD. This could lead to heftier service bills. So all those of you with latest merc diesels, check your engine emission norms. If its E-IV make sure you are putting in atleast API-CI4/API-CH4 and next year get API-CJ4 as it has lower phosphorus and ash which will protect your emission control systems to some extent. However LSD will ensure that your emission systems have lower life.
Shell Lubricants in the USA CJ-4 FAQ

To sum it all up, more than engine protection, the newer engine oils are designed from a view of protecting Emission and Post combustion diesel exaust modulation systems.

The only CI4 oil I could see in market was the MAK from BP. Its a mineral oil. I dont know about mobil 1 but I guess its CH4.

The real test of fuel vs car will come next year when CBU's from abroad which confirm to American Emission standards get hit with 500ppm fuel instead of the 15ppm they require.
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Old 16th June 2008, 14:28   #12
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Default Engine Oil Change - Still Black (Diesel)

Engine oil was changed for my Fiesta TDCi yesterday as a part of the routine 10k service. When I checked the dip-stick after driving back home, the oil was black, just like before it was changed.

I do know that in diesel vehicles, new engine oil goes black almost immediately as the engine is started. Why is this so?
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Old 16th June 2008, 14:58   #13
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Oil shouldnt turn completely black in under 100 kms especially since oil (i assume oil filter also) was changed in 10k kms car. Slight discoloration can be normal.
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Old 16th June 2008, 15:22   #14
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Not all oil gets drained when the oil is drained within 20 min of car being used i.e. within 20 min of stopping the car. This sometimes causes the oil to turn black almost as soon as you leave the Service shop. Please check out the oil. how does it feel. If it is sticky then the oil has not been changed.

Next time around please insist on changing the oil 20 after the car engine is switched off.
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Old 16th June 2008, 15:40   #15
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More than waiting, ensure while the oil is drained, open the filler cap to let the air in, wait for all the oil to drain out, will take 5-10 mts max. Again remove the oil filter and replace with new before you put in new oil.
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