>manufacturer knows best,<
They are only interested in selling the cars. They need to minimise costs for the first 3 years and maybe the first 60k miles to attract the fleet owners. Cambelt intervals have probably only been decreased by some makers because of the potential warranty cost implications and potential for bad press affecting sales.
Whay happens after 100k is of no consequence to the manufacturer.
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pmh (was peter)
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If the engine was only to last to 100,000 the taxi fraternity would have the maker in court faster than they take a punters tip!
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One of the most important parts of preventative maintenance IMO.
I've been a great believer in good oil servicing since i worked for a chap who had afleet of transits (this is back in the 70's), his first tranny!? as an owner/driver his oil changing was meticulous and his vans reached astonishing mileages (V4 petrols).
I've still run petrol cars but i've run diesels (i usually have one of each) since about '86 i think.
Without fail i would say my longest oil change interval has been 5000 miles but usually 3000, i don't normally go to the extra cost of fully synthetic because i know i won't be taking advantage if its supposed long life. and without exception the diesel engined cars (petrols probably as well but not so obvious) are always very much quieter following oil change.
I recently performed first oil change on hilux at 2200 miles and lovely wife commented on how much quieter it is especially when cold.
I would change annually regardless of mileage anyway if on a 2nd/classic.
Evedentially, right years ago i had a Renault 21 savanna estate diesel with 100k or so, i bought it used and it had one of the best service histories i've ever seen, 1 owner and oilchange evry 5k, at 150k the head gasket started to leak oil down the outside of block, so i stripped down expecting to have to at least have some worn parts; not a single sign of wear anywhere, just as well cos renault arn't afraid to charge for bits.
I worked for a chap who had imo the best maintained fleet of trucks in Northamptonshire, he bought British only (wouldn't have foreign vehicle in the yard) and his oils were changed at 15k engine, 45k gearbox and diffs, unheard of. But breakdowns wer virtually nil and owner drivers would queue up to buy them at 5 to 7 years old with 5 to 800k miles on them, running as good as new.
I'm touching a lot of wood here, but i've been lucky and not had problems engine wise really on any of my cars over the years, funnily enough i don't have any trouble selling either.
And though i'm not in the first flush of youth our cars get driven quite hard BUT always warmed gently before and allowed to cool before shutdown if td.
I know some will say i'm too fussy and that i'm wasting money, but hearing about the various problems (timing chain guides etc) that some cars have, i'm much of the opinion that oil degradation and in some cases blockages of minor oilways due to filthy oil cuses more problems than people imagine.
Ford ohc oil pipes blocking up i think 90% of the time was caused by old oil and rubbish going through the by pass valve and causing blockage, i never had a problem with cars i used to maintain in those days.
SWMBO, feels much the same and reckons the manufacturers dont want us running vehicles for 20 years (Volvo 240/700/900 Merc 124's Toyota camry etc) and have deliberately gone down the computerised route and extended servicing route to make the car seem attractive financially (plus all the toys most of which are only gimmicks that i for one dont want anyway) for its lifetime which as pmh says above seems to be 100k and get rid. And buy another (its all for the environment dont you know).
Interesting to see where this thread goes, should imagine there'll be generation differences of opinion too. (can hear the Dinosaur jibes already)
ttfn.
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I don't think either time or mileage are critical - as long as you don't take it to extremes.
My evidence for this is the relative rarity of lubrication based engine failures on the technical side of this forum. The raft of problems caused by long-life servicing predicted by the doom-mongers simply hasn't come to pass.
Of course there are people who will say that they have had such a lubrication based failure - despite this being costly, it isn't statistically meaningful. The number of users and posts on the technical forum does give more confidence in the results than anyones entire lifetime's car usage.
Failures and practices in years past really aren't of the greatest relevance (unless you run a classic!), as both engine technology, and more importantly oil specifications and quality are simply incomparable.
Now, many users of the technical forum are technically savvy, and wouldn't mistreat a motor car; but, there are a large number of non-technical people who drift in with a question when they have a problem. Most of these questions tend to be electronics - if they are oil questions, it's usually just that they haven't read their manual, and don't know what grade to use.
There are engines which need a very specific oil - 5W30 for Ford, the special oils for PDs, but the majority of engines are more forgiving of slight changes in oil grade and quality.
Having said all of this, I don't drive and maintain statistics, and so, I keep to the manufacturer's specifications.
Number_Cruncher
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Determination of the optimum oil specification and the optimum oil change interval requires thousands of hours of durability testing on numerous engine samples by the engine/car manufacturer in conjunction with the oil manufacturer. I follow the car manufacturer's recommendations.
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L\'escargot.
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most critical criterion, time or mileage regarding engine oil change frequency?`
Neither. Oil changes are not a critical factor at all in modern (i.e. 10 years old plus) cars using modern oils (i.e. not the bog standard oils used by quick lube service merchants in the USA). The only caveat is a few manufacturer's designs which have been shown to be prone to failures due to specific features - introduced by design or accident - eg black death sludge build up in some cars in the USA.
Unless you believe in anecdotal evidence and that Elvis was seen yesterday talking to the Roswell ET.
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I'm a time and miles bloke.
Low mileage, long time can result in condensation and corrosive oil.
High mileage just gives worn out oil....
Some years ago - Ex colleague 6 months in new cavalier and worn (to nothing) cams, destroyed followers at 30k miles on the original oil, just topped up. New engine, him sacked.
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Some years ago - Ex colleague 6 months in new cavalier and worn (to nothing) cams destroyed followers at 30k miles on the original oil just topped up. New engine him sacked.
The Cavalier mk3 had service intervals of 1 year or 9,000 miles, the recommended oil was 10W-40 API-SF - many of them didn't use much oil so top-ups won't have added much fresh oil.
Compared to modern oil, I'm surprised he got as much as 30,000 out of the engine.
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We came to the conclusion that mileage was on average a more critical factor than time for engine wear. (re oil change interval)
That is if either factor were significantly increased, but the other stayed well within manufacturers limits. Just an impression from the cars (as amateurs) that had passed through our hands to be serviced over the years.
Edited by oilrag on 23/12/2007 at 16:20
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We came to the conclusion that mileage was on average a more critical factor than time for engine wear. (re oil change interval)
Yeah, oil wears out but doesn't die of old age.
(on average, ignoring exceptions like grandma's car that does 500 miles a year and has the original oil in from 1990).
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Neither time or mileage should be the sole determining factor, in my opinion. The type of driving coupled with the number of miles and balanced against the manufacturer's advice would be my starting point.
My driving is 400 miles per week in two 200 mile trips on Motorway and Dual Carriageway at 70 mph, thus the engine is most often working at its optimum temperature, heating the oil sufficiently to drive out any condensation reducing the likelyhood of acidic residues from dissolving and causing problems. Even so, with my wife's car which does lower distance driving, on a daily basis, I only change the oil at 2x manufacturer's recommendation trusting that the oil's designed capacity for dealing with acidic deposits will neutralise them, and that its detergent qualities will hold carbonaceous residue in suspension, either for filtration or until an oil change. Determining the oil's lubricity is not really within the average motorists realm and somewhere you have to have faith in the product you are using. Briefly, short , cold engine trips combined with budget oil, consider more frequent changes, up the quality of oil and rest a little easier. Long hot running with premium oils then use manufacturers guidance. Extrapolate anything in between, but I, personally, wouldn't go outside of OEMs figures, which typically seem to be 10,000 miles/ 1 year.
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>>The Cavalier mk3
Yes, by the time that Vauxhall got to the mkIII, they had sorted out the necessary metallurgy to obtain a decent life from their camshafts in the OHC engines. mkIIs and their contemporaries would eat camshafts even if the 9000 mile service intervals were followed properly. In fact, swapping cams was almost bread and butter work in the Vauxhall garage where I worked - we had some special tools that enabled us to swap cams out without removing the head.
The process that they added was so-called TIG (no not the welding type) hardening, which was applied to the camshafts from about 1989/1990 onwards.
Number_Cruncher
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"relative rarity of lubrication based engine failures"
But how many are directly traceable to an oil problem? Assuming the manufacturer has done his sums right and has allowed just a short enough service interval for any failures to occur out of warranty, there is unlikely to be a proper post-mortem - the garage will simply replace the worn-out component and the driver will be none the wiser.
In any, the result of oil neglect is not always catastrophic. We have had two old cars with uncertain histories (but cheap) that had rattly camshafts for years. Not fatal, just noisy...
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Most oil based problems wont show up in warranty time (normally). But oil thats in too long a time in service will cause wear (and yes it does show as engines get older).
If you are only keeping a car for a short time from low mileage you are not going to see many oil based problems but get to cars of 7/8 years or older and oil problems become more of an issue. Worn rings, seals, lifters, cams and other components start rattling more. (rattles normally due to oil/wear etc.)
I do agree there are fewer bottom end problems than there used to be; but far more top end!
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Far more top end than when? Is this a gut feeling or do you have evidence it is the fault of the oil? If problems show, it seems to me far more likely that the users have neglected the basics, as many posts here show: regular oil level checks, manufacturers OCI and oil quality requirements etc. Posters here take an interest in things mechanical: most users are utterly oblivious, and many so-called technicians:)
Edited by nortones2 on 23/12/2007 at 21:17
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Regarding time interval,
I serviced an old Polo C doing around 2,000 miles a year (never fully warm) double the time interval. Either Duckhams or Castrol 15W40. Cam area remained spotless over years.
No signs of extra engine wear.
Re, Mileage interval,
I halved the oil change mileage interval on a Perkins Prima and after 70,000 miles or so, the garage asked me why the engine was so quiet compared with average.
Both of these examples refer to around 10 years ago, before some modern (low viscosity oil) engines came along that sometimes have a consumption related oil change built in between services.
Edited by oilrag on 23/12/2007 at 21:39
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Far more top end than when?
Than years ago. Bottom end problems were the norm. They have virtually disappeared (or are certainly less cost effective to sort when they do appear)
Is this a gut feeling or do you have evidence it is the fault of the oil?
Not evidence that would hold up in any court room; but certainly enough to prove to me that it is so. A couple of examples. I maintain an old fiesta (b 84) that was originally run on 20/50 (as per ford spec) and has since been run on 15/40 and then 15/50. the engine is in very good condition, serviced very regularly and has long since gone past the 100k mark. By contrast I also service some newer fiestas (same engine) that have always been run on 10/40 (as per ford spec) but serviced much less frequently. and are far noisier (rattles and stuff) and have covered less miles by a long way. They also use far more oil between services.
When ford changed the oil spec for these engines they did nothing to the engine. The fault of the oil or the service time? Difficult to say but probably some of both. Why? Because other engines serviced more regularly are less noisy. So its a comparison between older well maintained, newer badly serviced and newer well serviced.
Other examples include a cavalier versus newer astras. There are others too.
most users are utterly oblivious, and many so-called technicians:)
thank you ??
Edited by yorkiebar on 23/12/2007 at 22:44
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Going just a little further along, imagine you are the engineer responsible for a particular engine installation in a car. If you were setting the oil change intervals for the engine, how would you do it?
One extreme would be to run some test engines under the most arduous conditions imaginable, with regular oil analysis, deciding to change as soon as the oil began to degrade.
Another more pragmatic approach might be to run the engines under slightly less than the most arduous conditions, still perform regular oil analysis, and this time, allow some degradation - but still being fairly confident of a decent life for the average engine - although accepting that towards the end of this life, the engine will be noisy, and will be using oil.
Using the first extreme would probably leave you with something like a 3000 mile interval on mineral oil and a 5000 mile interval on sympathetic oil. This would be a good regime only for that truly tiny proportion of people who buy a new car, and run it until it has 500,000 miles on the clock. For the vast majority of cars, this is a waste, a waste of time, money, materials, and effort, as the car will almost certainly be scrapped for some other reason.
Erring towards the second more pragmatic approach, will certainly get all but a tiny number of engines out of the warranty period, and will even give the vast majority of engines an acceptable life. The motorist who wishes to break world records for mileage covered will probably be disappointed, but, how many cars are sold to these people. For most people, an adequate balance between engine life and servicing cost/hassle will have been reached.
It wouldn't surprise me at all to find that a non-trivial proportion of modern cars will go to the scrapyard without even their cam cover ever having being removed, never mind the pistons and crank (except for tappet clearance adjustment or setting cam timing during a cam belt swap).
Number_Cruncher
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" imagine you are the engineer responsible for a particular engine installation in a car. If you were setting the oil change intervals for the engine, how would you do it?"
I doubt very much whether the engineers get the final say. If they did I suspect oil change intervals would be halved overnight.
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I doubt very much whether the engineers get the final say. If they did I suspect oil change intervals would be halved overnight.
You speak for me there oilrag, strangely the recommendations vary worldwide for the same engine.
In Australia they recommend oil and filter for the hilux at 10000km (about 6250 miles ish might be wrong i've simply done 5/8ths), same vehicle in UK 9000 miles.
Before they start jumping up, i know its probably dustier there, can't imagine a Toyo engine getting much dust in the moving parts though.
Most of the lads on the hl forum in Oz do theirs at 5000 km.
And then of course there's atf, gearbox, axle, brake fluid, and fuel filter changes for us to argue about.
Big spoon goes to whom?
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I'd have thought that 20,00 miles in 2 years would be a good sign, but for the engine, 10,000 in 2 years might indicate longer on the road but just in town environment? That might mean clutch/brake wear, but not that the engine would be more worn?
Equally, time driven in hours might be an indicator of interior wear, contrast with one simply using the M1 with one person aboard. I reckon a full service history is all that really matters, and if higher mileage gets you a lower price, fair enough.
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There are similar variations between identical Subarus -12k in UK and 7.5k in US. Even those advocating short changes tend to use 6k in UK and 3k in the US.
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I doubt very much whether the engineers get the final say. If they did I suspect oil change intervals would be halved overnight.
Well, I suppose that does depend upon whether the engineer is any good or not. Any fool can design a system with a huge margin of safety, whether that margin is in how often you maintain the system, or how large and heavy you build it in the first place.
The skill comes in reducing these margins - making a part that's strong enough, but only just strong enough; specifying a service interval that is adequate, but not excessive.
Actually, the scenario of setting maintenance intervals after the engine exists as I mention above will probably never happen. It's much more likely to happen the other way round. The vehicle manufacturer will specify a list of requirements for the vehicle, in terms of performance, economy, total cost, maintenance interval, etc, etc, and the engineers will be tasked with designing a system to meet the requirements; verifying all the requirements by a series of analyses, inspections, design reviews, and final physical acceptance tests.
Number_Cruncher
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"Actually, the scenario of setting maintenance intervals after the engine exists as I mention above will probably never happen. It's much more likely to happen the other way round."
We all know the Fiat/GM 1.3 (fiat multijet 1.3) diesel is the same engine for both manufacturers.
Also that Vauxhall and and Fiat have greatly differing service intervals for this engine, with seemingly Vauxhall being more fleet orientated. (with all that could imply regarding servicing costs)
It seems to me its not a co-incidence that the Vauxhall run a longer oil change interval.
I contacted a Fiat dealer a while ago to see if Fiat they would allow a much longer (Vauxhall) service interval and low viscosity long life oil, in their version of the joint engine.
No way.
Sadly, I suspect the accountants are in charge of long life service intervals.
But then, I am a cynic ;)
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I am a cynic too oilrag, because I think your comment about the same engine having different servicing regimes dependant upon which vehicle it is in, says it all. For me anyway!
Service costs are a major selling point (esp to fleets) and the lower those costs the more attractive the car!
Don't see many Fiat fleets :). Must be too expensive to service/run !
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>>Also that Vauxhall and and Fiat have greatly differing service intervals for this engine,
Could it just be that Fiat are being excessively cautious? Is the minimum oil quality requirement the same in both applications?
Are these engines failing in Vauxhalls left, right, and centre?
>>Don't see many Fiat fleets
Mmm, can't think why!
;-)
Number_Cruncher
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