Engine oil black in a petrol car | Motoring discussion | Back Room Forum

Sat 9 Jul 2016 09:01

Engine oil black in a petrol car - Project C

Hi all

My previous experience of petrol cars is that the oil is gererally more honey coloured than black. Our corsa d petrol however the oil is black. It is still quite clear but much blacker than any oil I have seen from a petrol engine before. We bought it only a few months ago and the oil was more or less black then. Do you suppose it is just model specific or is there potential for an underlying issue?

Cheers

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Sat 9 Jul 2016 09:06

Engine oil black in a petrol car - NARU

How long and how many miles since it was last changed?

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Sat 9 Jul 2016 09:19

Engine oil black in a petrol car - RT

Oil in petrol engines gradually darkens over time - oil in diesels darkens much quicker, in 10s of miles not 1,000s.

To give yourself a firm baseline, change the oil and filter, and then continue checking.

Edited by RT on 09/07/2016 at 09:21

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Sat 9 Jul 2016 11:34

Engine oil black in a petrol car - Benet

you can certainly get jet black oil if you neglect changing oil and filter long enough!

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Sat 9 Jul 2016 11:45

Engine oil black in a petrol car - nortones2

My first car, Morris Minor, had black oil. Which was strange, because after I had it changed, it consumed oil at a ferocious pace. Stop for fuel, add a quart of 20w50. I knew nothing about cars so didn't think to check the obvious (now) before I bought the thing in 1968!

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Sat 9 Jul 2016 12:21

Engine oil black in a petrol car - Wukl

Cars I had when I was younger routinely had black oil, which I have always thought was carbon from the fuel, rather than being a product of anthing the oil was doing. We used to spend a lot of time with the choke on and carburettors weren't anywhere nearly as well controlled as modern fuel injection. An alarming number of metal shavings I used to find in the drain pan as well! My cars of the last decade have all had honey to treacle coloured oil. May be it is carbon, or may be it is the moved away from mineral to fully synthetic oil? I have to top-up my current wagon evry month, so it's always being diluted.

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Sat 9 Jul 2016 13:10

Engine oil black in a petrol car - craig-pd130

We have a 2010 Corsa D 1.2 petrol (the 82bhp version), it gets serviced annually and does around 10K miles in that time, mostly town / urban work.

We've owned it from 1 year / 10,000 miles, and after it's done a couple of thousand miles the oil on the dipstick is always dark / virtually black. The car runs fine otherwise. It will burn maybe half a litre of oil between changes.

As long as yours isn't burning too much oil, I wouldn't worry about it.

One thing I have noticed with the Corsa D petrols is, the spark plugs can loosen. They're only the small type and so cannot be torqued down too much, which means they loosen a bit as the crush washer settles.

A couple of months after new plugs have been fitted, it is worth checking they're snug. Don't heave on the plug spanner, just a gentle but firm check. Don't tighten more than 30 degrees / one-twelfth of a turn.

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Sat 9 Jul 2016 15:07

Engine oil black in a petrol car - Galaxy

When I lived in London the oil in my car engine used to turn black fairly quickly after being changed. Lots of short trips and being stuck in traffic jams certainly were major contributors to this.

However, since I've moved out of London and live in what is essentially a semi-rural area, I find the oil never really turns black anymore, not even when the car is due for it's service. It's always a golden / brown colour, now, I've never seen it black.

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Sat 9 Jul 2016 16:13

Engine oil black in a petrol car - John F

We have a 2010 Corsa D 1.2 petrol (the 82bhp version), it gets serviced annually and does around 10K miles in that time, mostly town / urban work.

We've owned it from 1 year / 10,000 miles, and after it's done a couple of thousand miles the oil on the dipstick is always dark / virtually black.

Well, it shouldn't be. The oil and filter in our 1.6 petrol Focus, over twice the age and twice the mileage, were changed over 1000 miles ago. The oil is still honey coloured on the dipstick (I've just looked).

When changing the oil, the car should be tilted towards the drain plug and left to drip for several hours to allow all the old grotty oil to drain away from the interior surfaces and oil channels, leaving them as clean as the sides of a nearly empty tomato sauce bottle. No garage will do this for you.

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Sat 9 Jul 2016 18:44

Engine oil black in a petrol car - craig-pd130

Well, it shouldn't be. The oil and filter in our 1.6 petrol Focus, over twice the age and twice the mileage, were changed over 1000 miles ago. The oil is still honey coloured on the dipstick (I've just looked).

When changing the oil, the car should be tilted towards the drain plug and left to drip for several hours to allow all the old grotty oil to drain away from the interior surfaces and oil channels, leaving them as clean as the sides of a nearly empty tomato sauce bottle. No garage will do this for you.

Different cars behave differently, John. I did state our Corsa does burn a little oil, which will inevitably cause some contamination of the oil with combustion by-products. But at a litre per 20K miles, I'm not worried about it.

I've had a couple of Mondeos with the 1.8 Zetec mill and neither burnt any oil, and I remember the oil did stay clean in both.

I don't know if it's a characteristic of all Corsa 1.2 / 1.4 petrol engines, or it's the way the manufacturing tolerances and running-in of the engine in our car that lead to the oil taking on colour, but I'm simply relaying my experience of the car for the benefit of the OP.

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Sat 9 Jul 2016 19:10

Engine oil black in a petrol car - Cyd

Different cars behave differently

Indeed they do. Mine, a tuned Saab 9-3 2.0T has it's oil changed every 5.000 (max 7.000) miles and I'm very particular about flushing with flushing oil and even a shot of ordinary oil to wash out the flushing oil. I run it on VPower or Momentum99, yet the oil is as black as the ace of spades every time I drain.

My wifes C1 on the other hand takes the same oil, I do not perform a flush yet even after as much as 10.000 miles the oil is a nice golden colour.

So, the OP's issue could be something or nothing. But I would perform an oil change to be on the safe side, it's possible it's not been done for some extended time (especially if the previous owner knew he was getting rid).

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Sat 9 Jul 2016 17:05

Engine oil black in a petrol car - Cyd

Hi all

My previous experience of petrol cars is that the oil is gererally more honey coloured than black. Our corsa d petrol however the oil is black. It is still quite clear but much blacker than any oil I have seen from a petrol engine before. We bought it only a few months ago and the oil was more or less black then. Do you suppose it is just model specific or is there potential for an underlying issue?

Cheers

If you do not know when the oil was last changed (or have any reason to be dubious about any records) then have it changed now. Personally I always service a car about 3 to 4 weeks after buying it irrespective of when it was claimed to be last done.

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Sat 9 Jul 2016 20:36

Engine oil black in a petrol car - gordonbennet

Not all Diesels fill the oil with carbon, the 3 litre D4D in our Hilux kept its oil clean for around 1000 miles and would only gradually darken after that, following oil drain (via the sump) the new oil would again be clean for the 1k so there must be very few oil traps.

The 1.6HDi Diesel of Doom we had and the family BMW compact would both have filthy oil within moments of re-starting after an oil change, i'm sure engines having traps where oil cannot escape from isn't helping carbon contamination problems, which the DoD suffers badly from, the BMW turbo failed (they all do that sir) at 45k, luckily under BMW approved used warranty.

All three of our present petrols, one inline 6 (20 years) one V6 (16 years) and one H6 (14 years) all keep their oils really clean for about 2k miles before they start to darken, none of them use any oil worth mentioning.

Daughter's new Civic type R blackened its oil very quickly, and it uses a fair bit too.

edit, none of us have a clue what son's 325i oil is like, no blinking dipstick, brilliant.

Edited by gordonbennet on 09/07/2016 at 20:41

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Sat 9 Jul 2016 23:42

Engine oil black in a petrol car - Big John

We now have 3 petrol cars in the BJ household.

Our old 2001 Skoda Octavia 1.4 16v(120k) and 2006 Fiat Panda 1.2 (33k) use very little oil and basically the oil seems to stay the same colour between services. Both only do less than 5k miles a year though (Octavia did high mileage earlier in its life - did burn some oil for a while which was simply the oil breather)

However my later 2014 Skoda Superb 1.4tsi does turn it's oil darker (not black though!) between services - even though I've selected 10k service intervals(don't think I'd like to run this engine on the usual long life servicing) . I did buy a bottle of suitable top up oil to reside in the boot - and as yet it's never been opened. Oil level doesn't seem to move! I seem to be doing about 15k miles /year

My previous 2003 Skoda Superb 1.9 pd always had black oil - even after a service

Edited by Big John on 09/07/2016 at 23:52

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Sun 10 Jul 2016 10:00

Engine oil black in a petrol car - John F

i'm sure engines having traps where oil cannot escape from isn't helping carbon contamination problems,

Good engine design should preclude this. However, I wonder if engines which are much tilted from the vertical to fit under a low bonnet might have traps which would otherwise not exist?

As diesel engines have compression ratios of sometimes double that of petrol engines it is not surprising that their dirty combustion products are more easily forced past the piston rings.

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Sun 10 Jul 2016 13:40

Engine oil black in a petrol car - focussed

i'm sure engines having traps where oil cannot escape from isn't helping carbon contamination problems,

Good engine design should preclude this. However, I wonder if engines which are much tilted from the vertical to fit under a low bonnet might have traps which would otherwise not exist?

As diesel engines have compression ratios of sometimes double that of petrol engines it is not surprising that their dirty combustion products are more easily forced past the piston rings.

Now superceded indirect-injection engines with CR's of 21 or 22 to 1 will foul their oil quickly - they are well known for it and have shorter service intervals to cope with it.

Current direct-injection engines with CR's around 17 to 18 to 1 will take longer, however, engine oil is designed to hold products of combustion in suspension, that's why the oil goes black, it's doing it's job.

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Mon 11 Jul 2016 21:04

Engine oil black in a petrol car - hillman

I would advise DIY. Change the oil AND filter now.

Every time you change the oil change the filter too. If you don't change the filter the oil will turn black during the first journey. Don't leave it to the garage. My favourite mechanic always uses flushing oil to get the engine clean before putting in the new oil.

Don't believe what the handbook says, that is written for fleet managers that want to minimise costs and sell on the car unserviced. Change the oil at half the recommended mileage, Or 5000 miles if you do much town driving.

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