Modern engines and extended service/oil intervals
Discussion
What's the deal? Can modern oils really cope with 10-15,000 miles per change or are the internet theories of 'planned obsolescence' true?
Regardless of vehicle, from a 1990 Yamaha v twin motorbike to an Audi TSI, I've always changed oil annually or at around 6000 miles, whichever comes first. I've never left it for 10k or more.
But I'm not an engineer so who am I to question the manufacturers recommended interval? Assuming OEM spec oil is used, is 10k or more per change going to do any damage? And on the flip side, is halving the interval (say 5000 miles) going to be more beneficial in terms of engine wear, or is it just a waste of time/money since the oil can easily cope with another 5000?
Regardless of vehicle, from a 1990 Yamaha v twin motorbike to an Audi TSI, I've always changed oil annually or at around 6000 miles, whichever comes first. I've never left it for 10k or more.
But I'm not an engineer so who am I to question the manufacturers recommended interval? Assuming OEM spec oil is used, is 10k or more per change going to do any damage? And on the flip side, is halving the interval (say 5000 miles) going to be more beneficial in terms of engine wear, or is it just a waste of time/money since the oil can easily cope with another 5000?
While I understand modern oils will be effective for longer than older ones from years back I still call b
ks on a lot of manufacturers service intervals. Especially gearboxes etc which they claim are "service free" or "sealed for life".
My understanding is a lot of these claims are to meet environmental regulations and the "Life" of an item for a manufacturer is 100K miles.
ks on a lot of manufacturers service intervals. Especially gearboxes etc which they claim are "service free" or "sealed for life".My understanding is a lot of these claims are to meet environmental regulations and the "Life" of an item for a manufacturer is 100K miles.
15k+ mile service intervals have been around for a long time so if there were going to be widespread failures because of it I'm sure we'd have heard by now. If you're determined to make an engine last 30 years and 500,000 miles come what may then sure, change the oil every 6k miles. But just following the manufacturer's schedule will almost certainly get you past the point where the car's not worth keeping from a rational financial point of view because all sorts of other stuff is failing. Our D5 Volvo has never gone less than 12k miles between oil changes and often over 15k; currently on 150k miles and going strong. So I tend to think the manufacturers do know what they're doing.
The long intervals are purely for the fleet market to make the total cost more attractive.
The car will be long out of warranty before the affects are realised.
If you buy a VW group product from new as a retail customer it will be set to 10k/12 month intervals.
If it a fleet car it will likely be set to longlife. Then when it hits its first service the dealer then decides to switch it back to 10k intervals.
Look at any ex shortish length lease car or ex VW group employee car. They will always have their first service at longlife intervals but then are now mysteriously on annual intervals.
The car will be long out of warranty before the affects are realised.
If you buy a VW group product from new as a retail customer it will be set to 10k/12 month intervals.
If it a fleet car it will likely be set to longlife. Then when it hits its first service the dealer then decides to switch it back to 10k intervals.
Look at any ex shortish length lease car or ex VW group employee car. They will always have their first service at longlife intervals but then are now mysteriously on annual intervals.
Many years ago I was introduced to Mobil SHC, which then became Mobil 1.
As an experiment, I decided to have 25,000 mile oil changes in a Rover 213 (from 8,000 miles)
Engine was like new at 150,000 miles, body fell apart due to rust.
In a non stressed engine where there is minimal dust in the atmosphere, there is nothing wrong with long oil change intervals when using synthetic oil.
caziques said:
Many years ago I was introduced to Mobil SHC, which then became Mobil 1.
As an experiment, I decided to have 25,000 mile oil changes in a Rover 213 (from 8,000 miles)
Engine was like new at 150,000 miles, body fell apart due to rust.
In a non stressed engine where there is minimal dust in the atmosphere, there is nothing wrong with long oil change intervals when using synthetic oil.
Could the same be said if the car was doing 3 mile work commutes for its entire life though? A bit different in that case Vs 25,000 motorway miles. Could be the difference between the engine developing an oil burning problem/compression loss and notAs an experiment, I decided to have 25,000 mile oil changes in a Rover 213 (from 8,000 miles)
Engine was like new at 150,000 miles, body fell apart due to rust.
In a non stressed engine where there is minimal dust in the atmosphere, there is nothing wrong with long oil change intervals when using synthetic oil.
I bought a pre-registered 2007 BMW 123d in January 2008 and paid for the 5 year Service Pack, which meant I had to stick to the service intervals displayed on the dashboard.
It had it's first service at 18K miles, second at 36K and third at 54K, all within the 5 years from 1st registration. It had a fourth service at 73K, but I sold it on 81K as I no longer did the miles to justify a diesel, had read of N47 engine cam-chain issues and had finally discovered straight 6 petrol loveliness!
It was still running just fine though and got an MOT in November 2023 at 132K, although that has now expired, so maybe the cam-chain finally became a problem?
I've had 6 higher mileage petrol BMWs from the mid-2000s since then and still stick to the 2 year intervals, but these days that tends to be after just 7/8K miles although after a service they tend to show at least 15K on the OBC until the next one is due.
Most of them got more use in their early years and seemed to be serviced at the longer intervals, but it doesn't seem to have done them any harm after 6 figure mileages in the case of 3 of them and 90+K for 2 more.
So IME it doesn't seem to be a major issue, although I have had gearbox oil replaced when they get leggier despite BMW claims they are sealed for life.
It had it's first service at 18K miles, second at 36K and third at 54K, all within the 5 years from 1st registration. It had a fourth service at 73K, but I sold it on 81K as I no longer did the miles to justify a diesel, had read of N47 engine cam-chain issues and had finally discovered straight 6 petrol loveliness!
It was still running just fine though and got an MOT in November 2023 at 132K, although that has now expired, so maybe the cam-chain finally became a problem?
I've had 6 higher mileage petrol BMWs from the mid-2000s since then and still stick to the 2 year intervals, but these days that tends to be after just 7/8K miles although after a service they tend to show at least 15K on the OBC until the next one is due.
Most of them got more use in their early years and seemed to be serviced at the longer intervals, but it doesn't seem to have done them any harm after 6 figure mileages in the case of 3 of them and 90+K for 2 more.
So IME it doesn't seem to be a major issue, although I have had gearbox oil replaced when they get leggier despite BMW claims they are sealed for life.
Roger Irrelevant said:
15k+ mile service intervals have been around for a long time so if there were going to be widespread failures because of it I'm sure we'd have heard by now...
Indeed. My old '02 BMW 3-series had variable length servicing and had to use 'long life' oil, so it has definitely been a thing for a couple of decades.By the end of my time with it the rest of the car was starting to fall apart but the engine was in rude health.
SteBrown91 said:
The long intervals are purely for the fleet market to make the total cost more attractive.
The car will be long out of warranty before the affects are realised..
Not that old nonsense. Cars can have extended warranty, they don’t then say, ooh, better make it every 6,000 miles then.The car will be long out of warranty before the affects are realised..
Truckosaurus said:
Roger Irrelevant said:
15k+ mile service intervals have been around for a long time so if there were going to be widespread failures because of it I'm sure we'd have heard by now...
Indeed. My old '02 BMW 3-series had variable length servicing and had to use 'long life' oil, so it has definitely been a thing for a couple of decades.By the end of my time with it the rest of the car was starting to fall apart but the engine was in rude health.
SteBrown91 said:
The long intervals are purely for the fleet market to make the total cost more attractive.
The car will be long out of warranty before the affects are realised.
If you buy a VW group product from new as a retail customer it will be set to 10k/12 month intervals.
If it a fleet car it will likely be set to longlife. Then when it hits its first service the dealer then decides to switch it back to 10k intervals.
Look at any ex shortish length lease car or ex VW group employee car. They will always have their first service at longlife intervals but then are now mysteriously on annual intervals.
^^ This is it, money saving for the first owner. Money pit for subsequent owners.The car will be long out of warranty before the affects are realised.
If you buy a VW group product from new as a retail customer it will be set to 10k/12 month intervals.
If it a fleet car it will likely be set to longlife. Then when it hits its first service the dealer then decides to switch it back to 10k intervals.
Look at any ex shortish length lease car or ex VW group employee car. They will always have their first service at longlife intervals but then are now mysteriously on annual intervals.
The pool Golf mk8 I was driving had longlife, but it was a diesel and the oil level goes up (the lubricant oil gets contaminated by the fuel oil). So it's just stupid to not change the oil. But they won't do it.
Acuity30 said:
Could the same be said if the car was doing 3 mile work commutes for its entire life though? A bit different in that case Vs 25,000 motorway miles. Could be the difference between the engine developing an oil burning problem/compression loss and not
There's the crucial part USE, short journeys kill oil; the pistons/rings & bores don't reach full operating temperature. This creates blow by of combustion gases which contain among other things water & unburnt fuel which is held in suspension by the oil. Ideally the water is boiled away when the temperature rises to +100°C.But of course it doesn't in such use and the pollution builds up in suspension in the oil, then the unburnt fuel dilutes the oil and disrupts it's lubricating properties; all shortening the projected life of the oil.
My car rarely gets warmed through these days and was way over time for an oil refresh, I did it last week and to my shame it stunk of petrol.
If you look at oil analysis threads on US car forums, where they take this kind of thing VERY seriously, they show engine wear increases with new oil, then levels out, then starts to increase again. So you can change the oil too often.
I recall one thread where they were testing oil every 1000 miles and were determined to let it go as long as possible. Despite the results still being OK, they chickened out at 11K as they just couldn’t bear to leave it any longer!
I recall one thread where they were testing oil every 1000 miles and were determined to let it go as long as possible. Despite the results still being OK, they chickened out at 11K as they just couldn’t bear to leave it any longer!
SteBrown91 said:
The long intervals are purely for the fleet market to make the total cost more attractive.
I don't think they've engineered the entire thing to save the 'fleet market' £400 over the term (2 additional oil services ) of a 3 year lease on a £60,000 car. I've run cars with 'extended' intervals and serviced them exactly in accordance with the manufacturers scheduled service requirements for almost 20 years and in all that time have had zero mechanical failures related to any relevant part of the car that would have anything to do with servicing requirements.
Heavy trucks have been on 100k (kms) oil service intervals for some time now, at least for those that are on manufacturers full repair and maintenance contracts which usually means leased for 3 or 5 years.
Interestingly, some of ours have needed rebuilds between 700/900k kms, but they are in use 24/7 and pulling maximum weights, usually replaced with new vehicles around those miles anyway with some needing engine rebuilds before resale.
Some needing no engine or other work at all would typically be in the hands of mechanically sympathetic (professional) drivers, ie warm up and cool down routines plus sympathetic driving, some needing engine or or other work at very low mileages have often been in the hands of incompetent uncaring (unprofessional) drivers...makes little difference to the operator because all such repairs are at maker's/dealer's cost due to full R&M lease deals unless obvious negligence/abuse such as massive overevving or run out of oil.
Remember trucks have oil spinners which remove a lot of the carbon crud from the oil, and obviously in those 100k kms the chances are a gallon or possibly two gallons of oil tops have gone in if the person behind the wheel checks levels and takes action.
This compares with Cummins engines of 80's design which generally covered 1+ million miles before needing work other than servicing incl torqueing injectors and setting tappets, but in a good operators hands with usually their own workshop would see fresh oil and filters every 15k miles...the same workshop swapped gearbox and axle oils every third engine oil change, hence 7 years hard work with barely a hiccup was the routine then sold on.
At the time you could buy a full rebuild kit for a 14 litre Cummins for under £1000.
You can hear the difference in the engine (tappet rattles etc) following that 100k km oil change on the modern engines, sadly oil pressure gauges are even disappearing from truck dash menus.
My own cars? every 3k or so for me, can't recall the last car i let run to 5k before changing the engine oil.
Oil doesn't to be made of unicorn tears, 20 litres of suitable oils can be bought for between £60/90 for the cars i run.
I also service the gearbox and drive train every so often.
Been very lucky over the years re vehicle reliability and yes some of it is luck, but like everything in life you can help hedge luck your own way by a bit of common sense prep.
I learned much from that operator i worked for in the 70's and 80's running multiple Cummins engines, he was a tight sod and wasn't into wasting money, but he always said oil is cheap, engine gearboxes axles recoveries and downtime are expensive and that hasn't changed.
Interestingly, some of ours have needed rebuilds between 700/900k kms, but they are in use 24/7 and pulling maximum weights, usually replaced with new vehicles around those miles anyway with some needing engine rebuilds before resale.
Some needing no engine or other work at all would typically be in the hands of mechanically sympathetic (professional) drivers, ie warm up and cool down routines plus sympathetic driving, some needing engine or or other work at very low mileages have often been in the hands of incompetent uncaring (unprofessional) drivers...makes little difference to the operator because all such repairs are at maker's/dealer's cost due to full R&M lease deals unless obvious negligence/abuse such as massive overevving or run out of oil.
Remember trucks have oil spinners which remove a lot of the carbon crud from the oil, and obviously in those 100k kms the chances are a gallon or possibly two gallons of oil tops have gone in if the person behind the wheel checks levels and takes action.
This compares with Cummins engines of 80's design which generally covered 1+ million miles before needing work other than servicing incl torqueing injectors and setting tappets, but in a good operators hands with usually their own workshop would see fresh oil and filters every 15k miles...the same workshop swapped gearbox and axle oils every third engine oil change, hence 7 years hard work with barely a hiccup was the routine then sold on.
At the time you could buy a full rebuild kit for a 14 litre Cummins for under £1000.
You can hear the difference in the engine (tappet rattles etc) following that 100k km oil change on the modern engines, sadly oil pressure gauges are even disappearing from truck dash menus.
My own cars? every 3k or so for me, can't recall the last car i let run to 5k before changing the engine oil.
Oil doesn't to be made of unicorn tears, 20 litres of suitable oils can be bought for between £60/90 for the cars i run.
I also service the gearbox and drive train every so often.
Been very lucky over the years re vehicle reliability and yes some of it is luck, but like everything in life you can help hedge luck your own way by a bit of common sense prep.
I learned much from that operator i worked for in the 70's and 80's running multiple Cummins engines, he was a tight sod and wasn't into wasting money, but he always said oil is cheap, engine gearboxes axles recoveries and downtime are expensive and that hasn't changed.
Sheepshanks said:
If you look at oil analysis threads on US car forums, where they take this kind of thing VERY seriously, they show engine wear increases with new oil, then levels out, then starts to increase again. So you can change the oil too often.
I recall one thread where they were testing oil every 1000 miles and were determined to let it go as long as possible. Despite the results still being OK, they chickened out at 11K as they just couldn’t bear to leave it any longer!
Since I made the thread I've been on a Youtube binge investigating this stuff. Basically every peer reviewed study in the past 60 years has concluded that driving the car frequently before it gets up to operating temp creates significantly more piston/cylinder wear than old oil ever will. Engines don't often fail due to bearing wear, which is the main thing fresher oil prevents, the vast majority go to the scrappers from piston/ring/cylinder wear which is pretty much entirely down to frequent short journeys. As a side note I found out prefilling an oil filter makes absolutely zero difference to engine wear, which is good because I've never done it and never suffered any repercussions. The filter itself gets filled with oil within 2-3 cranks on the starter, as can be seen on any transparent oil filter tests. I recall one thread where they were testing oil every 1000 miles and were determined to let it go as long as possible. Despite the results still being OK, they chickened out at 11K as they just couldn’t bear to leave it any longer!
Others may disagree, it's an argument older than the internet. I'll stick to my annual oil change because my annual mileage is 5000-7000 anyway, and it costs me £45 and half an hour out the year to do it.
GreenV8S said:
Sheepshanks said:
they show engine wear increases with new oil
That's unintuitive. Any idea what causes it? Maybe something to do with the new filter rather than the new oil?Gassing Station | Engines & Drivetrain | Top of Page | What's New | My Stuff