|
A comment on the Omega thread about the BMW 2.5 engine needing servicing every 6,000 prompts the question, how can essentially the same technology as used for example in my 2.5 Subaru engine (which requires 12,000 mile servicing) produce such a difference in maintenance requirements?
|
|
dont really know what answer you are after here, but one is a diesel and one is a petrol,does that help at all?
|
|
|
Isn't the BMW a diesel? And I don't think Subaru do a Diesel, so I presume you have a petrol?
Diesels produce large quantities of soot which is why they are like tractors. ;) That contaminates the oil so the oil requires more frequent changing.
For other cars, increased servicing intervals are there for the benefit of fleet buyers. If a car manufacturer can be convinced that his engine will survive 150k miles on the basis of 25k servicing, then if most of his buyers are fleet buyers he will save them a fortune. A sensible buyer who plans to own the car for many years might elect to change the oil every 6-12k miles and the car will last him 300k miles. Whilst this may reflect itself in lower residuals for the fleet operator, it is very difficult to predict depreciation, but easy to predict servicing costs.
Poor cars.
|
|
Those 2 particular engines aside....any thoughts?
|
|
|
Diesels produce large quantities of soot which is why they are like tractors. ;) That contaminates the oil so the oil requires more frequent changing.
This is not a particularly true statement. Diesels do generate soot which does help to blacken the oil quickly, but this is not why diesels required more frequent oil changes. The reason is that the extreme bearing pressures experienced in a diesel engine cause premature 'shearing' of the oil molecules thus causing the oil to totally lose its 'body' so to speak. However this is not now very relevant, given the new generation of ultr high anti-shear synthetic oils. This is why it is perfectly safe for a car driven mostly on motorways to do 20K between changes. Most modern cars are intelligent in this respect, and can adjust their service interval to match the type of driving, that why I was able to do 470 miles last Friday and the indicator only debited 400 miles off the time to service, whereas I may do a weeks worth of local driving say totalling 80 miles and I will 'lose' 100 miles from my time to service.
|
Not sure about diesels needing more frequent servicing than petrols.
VW have had the same fixed interval of 10k for a number of years.
Not sure if the variable service cars have any real difference.
--
I wasna fu but just had plenty.
|
Nsar
I have an oil change on my Forester every six months, irrespective of mileage. It costs about £40 including the filter.
--
Espada III - well if you have a family and need a Lamborghini, what else do you drive?
|
|
|
|
For other cars, increased servicing intervals are there for the benefit of fleet buyers. If a car manufacturer can be convinced that his engine will survive 150k miles on the basis of 25k servicing, then if most of his buyers are fleet buyers he will save them a fortune. A sensible buyer who plans to own the car for many years might elect to change the oil every 6-12k miles and the car will last him 300k miles.
I can't help thinking that this philosophy belongs to a bygone motoring era.
Regular changes of oil might prolong the life of the engine; although with modern oils I am far from convinced that this will have a significant impact.
However there are far more factors that determine the life of a car than the engine. Tin worm, suspension, gearbox, transmission, electrics/electronics, not to mention the many engine ancillaries that do not benefit from extra oil changes,
Most bangers worth a couple of hundred pounds have perfectly serviceable engines.
I don't believe that the effort and cost of these additional oil changes is justified as most cars will go to their automotive grave for reasons other than u/s engine.
|
I agree.... but I wonder what happens to engine efficiency
with less or more frequent oil changes..? What is 0-60
at 1 year versus 12 years..? What would compression test versus age reveal..?
I once knew a transit driver who thought it was always more efficient to change the engine rather than the oil... the oil was just topped up when needed..!
|
|
|
|
|
... produce such a difference in maintenance requirements
>>
the truthful reply is that servicing intervals are decided by manufacturer's based on three criteria:
1. how much they listen to lease company's demands to reduce maintenance costs.
2. their design engineer's judgement on how long a car can be safely left without servicing, without suffering too many customer complaints on breakdowns, and getting a bad reputation for reliabilty (and so ruin the manufacturer's future sales).
3. how much the servicng dealerships complain about lack of regular income from servicing business.
in this particular case, you could bet that if you left 1000 cars of each of the three makes (subaru, bmw, vauxhall) you mention unserviced for 5 years and/or 50,000 miles, just a handful of them would suffer any ill effects from the lack of servicing
this is related in a way to mazda-man's thread on the car which has never been serviced.
|
>>just a handful of them would suffer any ill effects from the lack of servicing
Just a handful of them would have died as a result of it. The petrols would probably all be poor starters, desperately needing new spark plugs. They would all be showing poor mpgs owing to blocked air filters and over-viscous oil. You'd be getting points left, right and centre for bald tyres. What you would miss out on would be known problems - like Alfa reducing the timing belt changing interval to 36k; like the need for regular coolant change in cars subject to HGF. Those would be car killers. For this reason nobody can say with certainty 'this new model will not have widespread problems for the next five years'.
|
|
Since when has tyre replacement been linked with servicing intervals?
|
The real point about this is dependability. Yes, some cars show no symptoms for a considerable time if utterly neglected. But when a symptom does show itself, in this case it's much more likely to be serious or even terminal.
But the most important reasons for doing these services are moral and aesthetic. It is quite simply disgusting to abuse machines, especially ones that are potentially lethal.
I call it 'cruelty to dumb machines'.
|
|
|
|
They would all be showing poor mpgs owing to blocked air filters and over-viscous oil. You'd be getting points left, right and centre for bald tyres.
>>
mappy : you are not thinking through your points today.
the items you mention in the above sentence would all get picked up in the mot test (emissions, bald tyres, etc. ).
and, as stated before, oil degradation issue is overstated.
|
|
|
|
|
