The colour of diesel oil?

[MikeeR]

Hi

Now this might seem like a strange question, but should my engine oil be very dark, almost black, only 200 kms after having a service?

I've done my own oil changes countless times over many years on the many petrol cars I've owned, but, so far, have only had dealer services done on my 2008 GTD MkV Golf. I'm used to oil remaining that slightly clear golden colour a least for a while before gradually darkening. I just had my 30,000 kms service done and the oil on the dip stick looks like what I would usually think of as old. But this might just be a diesel thing.

Can you help a diesel newbie?

Oh and the service seemed extremely expensive at 500 odd dollars.

Mike

[neil]

Hi

Now this might seem like a strange question, but should my engine oil be very dark, almost black, only 200 kms after having a service?

I've done my own oil changes countless times over many years on the many petrol cars I've owned, but, so far, have only had dealer services done on my 2008 GTD MkV Golf. I'm used to oil remaining that slightly clear golden colour a least for a while before gradually darkening. I just had my 30,000 kms service done and the oil on the dip stick looks like what I would usually think of as old. But this might just be a diesel thing.

Can you help a diesel newbie?

Oh and the service seemed extremely expensive at 500 odd dollars.

Mike

Yes it will go black but I would have thought it would have taken a bit more than 200km to do so.
I find that stupid dip stick hard to read being black and your trying to find the level of black oil.
I would have thought you would have picked up on the black oil sooner than 30000km.
Cant comment on the servicing costs as I'm yet to hit 30000 but 15000 was about $290 from Central Coast
which was the cheapest from the quotes I got.

And welcome to the forum Mike.

[Mk1_Citi_Golf]

Dependant on how black the old oil was, it would go black within a few seconds of start up due to old oil still in pockets in the engine. Most of the black in diesel engine oil is soot. (With my old GTD you only have to put the oil container within a meter of the car and the oil goes black! lol). Gas and petrol engines run much cleaner. Not only that, some services are done very quickly so there will still be some old oil left in the sump. (simply put, take a glass of water and put a spoon of milk in it... hey presto, a glass of milk). You can usually tell if it has been changed though by pulling the dipstick out, wipe a small amount on the back of your hand, put the dipstick back and then lightly spread the oil on your hand with a finger. If it's been changed recently the further you spread it the lighter it goes. If it's old oil you'll have an ever growing black circle. Good luck!

[MikeeR]

Thanks for the replies.

I guess I hadn't checked the condition of the oil so soon after a service in this diesel before, any time I'd checked it it had looked pretty dark.

The previous service with this dealer, the 15k kms one, was cheaper, but still $380 I think. They're on the northern beaches of Sydney so probably one of the more expensive around I would guess.

I'm interested to hear about diesel blackening the oil quickly, I guess that's what I wanted to hear. I was worried that they may have forgot to change it at all. I'll have another look tomorrow and try the smear on the hand test.

And yes the black dipstick is very hard to read - why do they do that?

[gldgti]

ofcourse its all dependant on driving etc, but in my experience with vw diesels it takes around 1000km to get hte oil nice and sooty again - but mk2GTD is correct- your oil is likely just dirty because of a little old oil left.

i dont know what newer diesels sumps are like, but with the old pressed steel sumps on the mk1-mk3's, you hardly ever are able to drain ALL the oil out - theres always about a tablespoon left. then theres oil that hangs around in the galleries in the block..... and if they are ultra quick with the service, there couple be plenty of oil left in the engine.

dont worry

i've been going well on my current change of oil as far as cleanliness, but that because i did 2 oil changes in the space of 1000km (fully synthetic too - ouch said my wallet).

[Greg Roles]

Diesels contaminate oil at an alarming rate, but given the 18:1 compression ratio, you can start to understand why some of the exhaust gets past the piston rings! The MKV oil cooler / filter holds a good 200mL of oil, and this isn't ever completely drained via the sump bolt. The oil filter has one way valves so it always has a "head" of oil to get to the turbo bearings quickly on startup. I drain this extra section when I do my own changes, but a dealer etc wouldn't bother. I find black as black oil each change, and I'm doing the 7500 inbetweens.

A VW specialist will save you at least $100 a service, I paid $326 for the same service at a specialist who is passionate about VAG and my business!