oil goes black very quickly

[Red Ed]

I changed the oil in my 1.9TDi and my motorbike. The oil in my bike after a hard 50 miles is still a lovely golden orange whereas the oil in my car was blackened by the time I'd run the engine for a couple of minutes. Is this normal?

[Crasher]

Yes, it is a diesel. I have had stress with customers accusing me of not changing the oil so many times over the years it is stupid. Once I had the good fortune of doing an oil change with a major VW magazine editor watching me as I worked, OK he is a friend but still… Two days later the owner fell on me like a tonne of bricks literally screaming at me accusing me of being a thief and con man. I put him straight immediately and suggested he called the said magazine and the Editor would tell him that I had done the oil change whilst he watched, I never saw him again which is not fair as I had done the job. Diesel combustion causes enormous soot deposits in the sump compared to a petrol engine. I tried an experiment once, I changed the oil of an old 1.6 D engine until it stayed clean after a few minuets, at least that was my intention. After four oil changes I gave up! We have a saying in the trade, “only a fool is pleased when his oil stays clean”, basically if the oil stays clean it is not doing its job but diesels really can throw people.

[kite]

Better the contaminants in suspension in the oil then lurking in the sump....

[Red Ed]

That's a great story Crasher. Very reassuring! Even so it looks like my car will be getting another oil change as I left the sealing washing off the sump plug!

[Crasher]

Better the contaminants in suspension in the oil then lurking in the sump....

Exactly.

[onzarob]

That's a great story Crasher. Very reassuring! Even so it looks like my car will be getting another oil change as I left the sealing washing off the sump plug!

oops...been there too