I was under the impression the oil should be changed after approx 1500-2000 miles on a new engine.
In the old days maybe, but technology and oil quality has moved on somewhat over the years. I believe manufacturers used to put in what was called a *running in oil* and that had to be changed within 1000 miles on a new engine, but nowadays its all different. Take Vauxhall for instance, they recommend an oil change at 20,000 miles or yearly - whichever comes first. Not sure if same applies to diesel engines, but I guess it will be at least around the 10,000 mile mark before a recommended change is necessary.
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Engine manufacturing tolerances are so good now that you don't need to 'run in' at all, really. The first 1000 miles or so limit the engine to 4,000 revs. Less on a diesel I guess, and then increase the limit by about 1,000 revs every 1,000 miles until you get to the red line.
Oil change should be after 1 full year, or 12,000 miles, particularly if you're moving to full synthetic, because the engine needs to loosen up and bed in.
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Co-incidentally I've just answered a question on another forum concerning oil change intervals, this time with a Rover 75 CDT (BMW diesel engine). Here's the essence of what I said, which I think confirms the answer that DD and pettaw gave to dg1, i.e. trust the manufacturer's advice ...
I generally advocate oil changes at shorter intervals than car
makers suggest (except in the case of fully synthetic oil). However I doubt if any undue engine wear will take place in the Rover 75 CDT engine if oil changes are left to the recommended intervals (15,000 miles or one year) for the following reasons ...
I worked in diesel engine design until I retired a couple of years ago and my oil specialist colleagues found that the most important factor dictating oil change intervals in diesel engines is the carbon (soot) content of the oil, which must not be allowed to exceed 2% by volume. With its large oil capacity and very clean-burning engine, the Rover/BMW engine will be well under 2% at 15,000 miles. The oil in older diesel designs would often be black within a very few miles, within minutes in many cases, but pull out the dipstick and take a look at yours and I think you will be surprised how clean it looks (and is).
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Dizzy very interesting, and knowing you as an ex Perkins man would value your opinion on my wife?s car which has the Prima TD engine.
This has a recommended oil change interval of 12000 although I have always carried this out at 5000.
Used mainly for short runs the oil does indeed go black very quickly.
Would you include this engine in the older generation of diesels and why do some engines get the soot content of their oil so quickly.
What oil change interval would you suggest for the Prima?.
alvin
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Alvin,
We used to get lots of reports from owners of exceptionally long and trouble-free life with the Prima, though these were more from van owners with the NA version who wrote in to say that, typically, they had knocked close to 250,000 miles on the same engine. I wish I knew how frequently they changed their oil, though I suspect that it was at the specified intervals. Even though they were not turbocharged, I suppose the build-up of soot contamination in the oil wouldn't be that far apart from the turbo version in your wife's car. Far less cold starts though, I would think.
12000 mile oil change intervals does seem fairly 'new generation' but I think I would play safe and regard it as 'older generation' when it comes to the clean oil issue (it's certainly in that era for exhaust cleanliness!).
If it were mine, I would change the oil more frequently than scheduled, perhaps at 8000 miles. This is purely a guess as I have no 'inside information' whatsoever on the oil performance with this engine and I must admit to being surprised to learn from your posting that the scheduled change was as high as 12000, considering that the engine was designed 20 years ago.
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It has dawned on me that I'm not quite up to speed when it comes to the servicing requirements of what Alvin aptly calls 'new generation' car diesels. Too much of a theorist and not enough hands-on experience! Reasons as follows ...
The 95000-mile Rover 75 CDT owner whom I was discussing oil changes with on another forum wrote back to say that his oil was in fact quite black after 7500 miles, contrary to my suggestion that it should still look fairly clean since it is a clean-burning engine with a large sump capacity. It has now occurred to me that very little carbon (soot) is needed to blacken oil and I wonder if we should totally ignore the colour as a pointer towards the need for oil change in diesel engines, even though soot content is a crucial factor.
Any comments from the diesel freaks, please? I suppose I'm one (diesel freak) now that I have a Rover 75 CDT myself, but it has covered only 230 miles to date so I haven't learnt much from it!
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Thanks for the advice on engine oil changes. Does anyone have any ideas about gearbox oil? I\'ve always understood that new gear-box oil can contain shavings from the cogs bedding in and should be changed fairly soon to stop these metal filings from causing further damage to the gear-box. Again , the dealer told me that 10,000 miles / 1 year is sufficient even, from new.
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The oil most manufacturers put in engines on the assembly line is not what they recommend for service;it has less additives and is designed to assist the bedding-down of the components-leave it in for the rcommended time-if you change it earlier on a diesel,you may find that your oil-consumption remains high for longer than normal.
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Ignore the colour of the oil. Modern synthetics are designed to remove soot. If you check the oil it will be black after a 1,000 miles. If the vehicle uses synthetic leave it until the service as specified - it's expensive stuff to waste. Audi variable servicing using castrol full synth regularly gets to 25,000+ miles before indicating a service is due.
Castrol have an engine on a testbed which has done over 100,000 miles on their fully synth. Regular removal of the oil and checking of the engine has shown little deteriation of the oil and virtually no engine wear.
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Just a quick point. You should also note oil should be changed every 6 months as well as to the miles specified. The oil degrades after time and if one drive 6k miles per year, it should be changed twice in that year and not at the end of that year.
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Interesting counter-intuitive advice from daveyjp. The point about cost is a good one, but I am now wedded to changing oil every six months, come hell or high water. HJ and many others have advised so many times that there is little more beneficial to an engine than frequent oil changes, and some almost go so far as to suggest that you can't do it too often. I don't suppose daveyjp's advice is specific to diesel engines, is it? I'd be interested in other opinions on this crucial issue.
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Not only diesels. Audi petrol engines are on variable servicing too, but from what I've read intervals between changes tend to be shorter - less than 20k. If a service is not indicated after two years a service is required anyway. The A2 has just done 10,000 miles and is indicating 16,700 miles before the next service - this hasn't changed much since I bought it when it had 4,000 and was indicating 24,000 miles to next service. Looks like I won't reach the indicated level inside the two years - unless it drops dramatically due to my driving habits - but with 6 months ownership this doesn't look likely.
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