fazzy wrote: ↑Sat Feb 23, 2019 9:15 am
Manufacturers will promote long life and fewer oil changes, telling their customers that it saves on maintenance costs. They will tell you about phenomenal new technologies in the oil industry... End of the day it's all marketing bull s**t.
What they don't tell you is that for the manufacturer it is better for you to make fewer oil changes than in the past, because the potential repairs are far more worth to them, then just charging you for labour on a oil change.They just want your car to go trouble-free for the duration of the guarantee period. After that, you are on your own and you pay for repairs. Manufacturers will be more than happy to issue you with an invoice thereafter
Oil technology has changes, albeit not too radically... however physics have not changed at all. When you run metal against metal, there will be metal filings as a result.
There may be more, there may be less... but they will be there
If there weren't any, we would never have engine failures
And I don't care what oil you use.
One of the main functions of motor oil is to reduce friction and wear on moving parts - reduce it. Not eliminate it.
That means that the metal filings stay in a closed loop until you change the oil and the oil filter. Someone might argue, that that's why you have an oil filter!! Yes, indeed... but the filings have to get there first and believe me... some parts of your car are more forgiving then others. Your turbocharger is one of those parts which is not that forgiving
End of the day, you pay your money, so you decide. I change my oil every 12-15 thousand kilometres. Bearing in mind the cost of an oil change, I say that my car also deserves a bottle of good whisky once in a while just like I do.
And that is all we can go by. None of us have tested the properties of oil after 10,15,20 or 30 thousand km's. And that means, that anything we say is based either on logic and our common knowledge or... marketing. I prefer to trust the first.
Do you honestly think VW want your car to fall to bits at 4 years old? They have a reputation to uphold, and if everyone was facing a hefty bill at 4 years old, they would never buy another VW. VW aren't the most reliable within warranty these days, but usually something major is going to go within warranty (part manufacturing defect, not apparent at the point of assembly) rather than at year 4. Citing reliability at 6+ years is a bit of a crapshoot because if it's had 2 or 3 owners, you don't know whether regular maintenance has been performed.
Long life services are fine when used as intended - if you are doing a lot of miles in a short space of time. The vast majority of engine wear occurs at cold start-up, when no oil is flowing and it is bare metal on bare metal, and thereafter, to a lesser extent as the car is warming up and the oil is more viscous, so the oil does not flow optimally.
If you are doing a 10 mile journey, and your car takes 5 miles/8 minutes to fully warm up, you've got 5 miles with very little engine wear. Take someone else (driver B) then doing 25 miles each way, they're going to have the same wear for the first 5 miles, then negligible wear for their next 20. Driver B's engine is going to suffer only 40% wear average per mile that you are. Less wear = less metal for the filter to capture and retain. Long life oil changes are perfectly acceptable IF you are doing high mileages, that oil will be stable for 2 years use if it is fully synthetic.
Oil tech has improved, fully synthetic oils now have more even viscosity across the operational temperature range, right from start-up to warm engine, making them easier to pump, even from cold - Dark-cze has commented on how thin 0W20 fully synthetic is, it is that way by design to pump well from cold - just because it is thing from cold does not mean it will be a poorly performing lubricant, and it won't get significantly thinner with an oil temp of 90C, nor will it degrade within its intended service life - all this helps reduce initial wear vs mineral oils.
Filings/particulates get generated with wear and have to reach the filter first to not continue to cause damage as you have said, but whether you are on long life servicing or not, this is the case for both scenarios, unless you would be generating that many particulates in long life servicing that you would overwhelm the filter and those particles would remain in the oil (which isn't going to happen). The oil filters are effective at doing their job and capturing the debris to prevent further circulation.
In his final year of Uni in mechanical engineering, my nephew did a study on automotive engine wear. He asked his local Ford dealership to retain oil filters from services and determined the amount of engine wear by materials captured by the filter, referenced by the number of miles that the car had done between services, for 1, 2 and 3 year old cars.
Engineering tolerances are that small now that on like-for like mileage samples, the year 1 service (with all that running in and first year's wear) only had 20% more metal particulate matter than for years 2 and 3. The high mileage samples (15-25k miles pa and 26k miles +) had far less metal particulates than the lower mileage samples.
Even on the low mileage samples, worst case for metal particulates worn and lost to the oil filter in first year servicing was 230mg (about 3 cubic millimetres).
If you are doing less than 12k miles pa, I would go for annual oil changes, and still use fully synthetic oil. If you are doing more than 15k miles pa, I would definitely be ok with long life servicing - as they'll be suffering far less wear (and causing less particulate generation) per mile.