Can oil last 20,000 miles?

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Is there any harm in changing your oil more regularly than the official recommendation? I dont think so. And its not expensive to do

If you read the American forums on oil analysis, where they take this sort of thing VERY seriously, it is suggested that new oil inreases wear slightly, then it levels off, then increases again.

Was discussed the other day on a VW Tiguan forum I'm a member of and one of the US members takes an oil change kit on road-trips (3-4000 miles) and changes it mid way! Oddly (to me) they seem to think steady running is worse than mixed use.
 
Actually it's possible there is. A report showed that the build up of anti-wear coating on engine surfaces was removed by the new oil so that wear rates increased for a period until the coating was built up again. I'm a fan of regular oil changes and do mine every 5000 miles which for me is 12 months. I would run it a little longer than that if it wasn't for the expectation of an annual service. For higher annual miles I would not consider doing it more often than 6000 miles.
Was there any mention of how soon the protective layer returns?
 
Again though, many of these cars will have been scrapped now at twenty years old, the vast majority with perfectly good engines (eg M112,113 from the early 00s) and most will have 100-200k miles and only serviced when required :)

The remaining ones are still running perfectly well and very few will have had oil changed 40 times in 200k miles ;)
Big strong nasp petrol without vvt, direct injection or too much emissions gubbins. As good as it gets for handling neglect 👍 IIRC my E320 had an 8.5l oil capacity, that surely helps.

An M271 or BMW N47 might not last so well! Talking of which - some of those modern BMW engines end up in a shocking state on extended changes!
 
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Was there any mention of how soon the protective layer returns?

As Rory said above, the answer is on the US oil forum Bob Is The Oil Guy but frankly your eyes might glaze over before you found it. From memory it was as much as 1000 miles but I might be wrong.
 
My 186K 1.9 PD TDI I've had nearly 8 years and in that time I've only done 26K and changed the oil 12 times , sometimes only 1300 miles apart .

The PD camshafts need a very high anti wear oil due to narrow exhaust and inlet lobes due to the four wide 'unit injector' camshaft lobes taking up the space .

The narrow lobes experience high loadings with their bucket tappets , missed servicing or a lesser oil and the narrow camshaft lobes wear down .

If this 1000 mile thing were true my PD camshaft would of been goosed a long time ago .

This high anti wear oil I use in everything applicable.
 
The narrow lobes experience high loadings with their bucket tappets , missed servicing or a lesser oil and the narrow camshaft lobes wear down .

I've heard about these VW Pump Duse engines that drive the injector pumps off the cam. The VW oil spec for those engines must be amongst the best or even the best available. More than good enough for a MB ?
 
Is there any harm in changing your oil more regularly than the official recommendation? I dont think so. And its not expensive to do

If nothing else it aids to keep the oil ways clean and on modern engines, thats important, its not the engine that fails but things like the turbo can suffer early failure??

each to their own..
It will be doing tremendous harm to the environment. No good reason to change oil more than is recommended by the vehicle manufacturer.
 
The other side of it is buying new cars because of premature engine wear is bad for the environment .

Used engine oil is recycled anyway and I always dispose up the council dump .
 
If you read the American forums on oil analysis, where they take this sort of thing VERY seriously, it is suggested that new oil inreases wear slightly, then it levels off, then increases again.
This is indeed correct, it takes a few thousand miles or at least 1000 hours to establish a base line. I'm of the opinion for cars that do average miles oil service should be annually. Anything more is wasteful.

I have attached a sample analysis of a new industrial/marine generator we had fitted back in June (we actually fitted 2 of them). They have just run through the first oil service and we see things like silicon from the gaskets and copper from the oil cooler increasing due to the acids formed with combustion byproducts. This will fall away to near zero again over the next 500 hours. Both engines are pretty much identical in their analysis reports. The absorbed soot level has increased steadily over the service cycle so the bedding in process is pretty much complete. These engines have standstill heaters so are never cold started, and thicker oil has better filming abilities for immediate stand by duties.

These analysis results are vital to upkeep, the usual indicator for us of an end of service life engine is increasing iron content coupled with a rise in zinc and then copper, indicating that the white metal shells have started to wear into the copper backing (usually on the edges first) and charecterised by falling lube oil pressure at high load.

This engine has about 12-13 liters more oil than the previous version (now a 55 liter sump) and the oil change interval has been upped to 500 hours instead of 250. Gensets tend to foul the oil up quickly if incorrectly loaded, hence the seemingly short oil life. Lube service is all these engines really need, aside from heat exchanger cleaning every 2000 or so hours. We only use 15w-40 because the engine has a ceramic monolith particulate filter and synthetic oil when it burns produces too much sulphated ash which clogs the filters up really quickly. The engine runs with a load factor of about 68-80% and will run for 12000 hours before needing a rebuild (hopefully).
 

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It will be doing tremendous harm to the environment. No good reason to change oil more than is recommended by the vehicle manufacturer.

I don't think that you're doing it right. Are you covering the hole with soil when you're done?

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Big strong nasp petrol without vvt, direct injection or too much emissions gubbins. As good as it gets for handling neglect 👍 IIRC my E320 had an 8.5l oil capacity, that surely helps.

An M271 or BMW N47 might not last so well! Talking of which - some of those modern BMW engines end up in a shocking state on extended changes!

Both M112/113 came with forced induction as well as in naturally aspirated format. Neither suffer as a result from 2-year service intervals - I’ve seen plenty with 200k+ miles and they won’t have had their oil changed every 5k miles either. It’s not neglect to follow the service specifications from the manufacturer is it? The point with those is they’re two decades old and most of their cars will have been scrapped due to other issues unrelated to whether or not the oil has been changed 10, 20 or 40 times in that time.

Older engines tend to have less precise fuelling and engine management - and used to suffer more from overfuelling (bore wash, oil contamination etc). Not sure I follow the issues you mention on that basis. That’s why older cars - say 1980s MBs, with mechanical fuel injection and only basic mixture control - had 6k mile service intervals, oil technology wasn’t what it is today and neither was the fuelling.

The M271 has a flawed (simplex) chain drive system unrelated to changing oil prematurely or not. You’d be better off spending the money wasted on oil changes replacing the chain and sprockets on that instead ;)

No idea on the BMW but surely that reflects on poor engine design if they’re unreliable when following the manufacturers servicing schedule. BMW are known for making a few chocolate engines over the years.
 
Semi or synthetic oil has little to do with ash it's the levels of ZDDP .
Kind of, but not. Straight mineral blends like 15w40 have about 400-450ppm Zinc diphosphate additives in where as the lower viscosity stuff is well over 2000ppm. Its a big enough difference to cause problems. (in my specific application anyway)

Its more to do with the burn rate of the oil. 9.0ltr engines like those in my example have a specific lube oil consumption figure, up to 30ml per hour is normal, about 14-15 litres of top up between service cycle, this will drop away on straight 15w-40 to about 10-11 liters until the towards the end of the life cycle, but on synthetic it doesn't, it remains pretty much constant, hence the higher ash production. Combined with diesel additive byproducts when you chow through 50-60 litres an hour of diesel makes that resulting ash product difficult to degrade fully.
 
I thought you were supposed to mix it with creosote and paint the fence? ;)
Paint your fence and use the left overs to underseal your car. Recycling at it's finest. If you have access to a centrifuge an indirect injection OM lump will drink a gallon or two also. :D
 
Both M112/113 came with forced induction as well as in naturally aspirated format. Neither suffer as a result from 2-year service intervals - I’ve seen plenty with 200k+ miles and they won’t have had their oil changed every 5k miles either. It’s not neglect to follow the service specifications from the manufacturer is it? The point with those is they’re two decades old and most of their cars will have been scrapped due to other issues unrelated to whether or not the oil has been changed 10, 20 or 40 times in that
I don’t think anybody is arguing for 5k oil changes - just that extending to 20k might be a decision based more on accounting than longevity. As seen with ‘sealed for life transmissions. Especially with most engines being highly stressed, small capacity turbos now. The days of engines as hardy as the M112/3 being sold in this country are sadly long gone.

With the extractor, I can change the oil in the time it takes to have a cup of tea and under £40. It barely registers on the cost of running.
 
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On the topic of engine oil spec.... an observation: it is interesting to note that the majority of car manufacturers have just a very small number of oil specification to cover a very large variety of engines.

In the case of MB, 229.5 is the recommended engine oil for almost all MB petrol and non-DPF Diesel engines, and 229.52 for all PDF-equipped Diesel engines. This is in spite of the fact that MB engines across the years and cross the engine model range are using vastly different technologies.

So it would seem that the engine oil spec represents what the manufacturer believes a good engine oil should be, rather than a specific fit to this engine or the other.

The same applies, BTW, to MO tyres - they are the same regardless of whether the car is a FWD A-Class or a RWD C-Class etc - so it would seem that the MO standard represents MB's general tyre preferences rather than a specific fit for a car model or suspension setup etc.
 

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