In advertisements for sale, it is difficult to find a car's mileage of more than 150,000 thousand kilometers. After overcoming this magical milestone, almost any car immediately goes in search of a new buyer. After 2-3 years of operation, we again see it on sale ... with approximately the same mileage. The cycle of mileage in nature sometimes takes on a bizarre look - a friend once showed me an accidentally found statistics - the history of publications of advertisements for the sale of a car that now belongs to him for several months. Miracles - the price gradually increased, and the declared mileage decreased. All categories of car owners - sellers and buyers - are afraid of frightening figures noticeably higher than 100,000 km. A car with a mileage of "250,000 km" is automatically synonymous with "about to landfill." The specified mileage of 140,000 km, for a car about 20 years old, automatically makes it the number one candidate for the bride.

I have already casually referred to the topic of mileage from the point of view of the internal combustion engine resource several times in various articles. Many basic concepts of the relationship between resource and mileage really lie on the surface, let's try to put them together:

The basic value of a resource in the professional sphere is engine hours- the operating time of the unit in the set mode is a more accurate value characterizing the resource. Let's say that a diesel generator has successfully worked for 10,000 hours at constant speed - we still repair it as planned, according to the regulations. The mode is so monotonous that the "resource" is obviously worked out almost exactly according to the operating time - there will be no surprises. We continue to operate further - the probability of failure increases. Most likely, this was determined at the time of the development of the unit. It is easy to predict this - the engine operating speed is constant at 1500 rpm. The expected 10,000 service hours is something like 416 days of continuous operation. 900 million wear cycles. Having recalculated the effective power of such a generator and the used revolutions for the "automobile" mileage, we get something about 1 million kilometers. When using standard (ordinary, and not the best, in this case) materials, the resource (mileage) is sufficient for all possible economic needs. Approximately the same mileage is found in commercial vehicles - the operating mode of trucks is close to the "theoretically ideal" operating mode of the engine, slightly differing from the diesel generator.

For a car, unfortunately, this value is not very convenient. The problem is that there is no "set operating mode" here. There are too many unknown values ​​to be "attached" to the objective characteristics of the resource, be it kilometers or engine hours.

X value - speed variability

The range of possible revolutions of a modern internal combustion engine is an impressive value. Typically something around 600-6000 rpm. The difference is an order of magnitude. Approximately 5400 possible engine operating modes within this range! At least three zones of efficiency - low power and low torque (low rpm), medium power and high torque (medium rpm), high power and low torque (high rpm). The edges of this range are obviously best thrown away and never used, confined to the range where combustion is extremely efficient - something around 2000-4000 for a modern motor. It turns out great: efficient combustion, almost constant high pressure in the lubrication system - the resource will be stable and almost infinite.

In return, however, we get a wild absolute fuel consumption, a tendency to overheat - why does the engine revs 2000 rpm at the time of idleness - wasted fuel for nothing? You can force yourself not to spin the engine above 4000 rpm, but it’s harder to get rid of low rpm, idle rpm. Therefore, having excluded the most harmful mode - an extremely ineffective and extremely useless "idle" in the region of 600-650 rpm, we got rid of many problems with the resource, but at the cost of an extremely ineffective consumption of the energy received. You will not spend money on repairs - you will spend money on gasoline and the fight against overheating. Unfortunately, we postpone the option with "narrowing" the effective speed range to ensure the stability of the resource estimate in the engine hours of the engine operation - this is economically unprofitable. Environmentalists will protest and refueling every 100 km will not suit you. We will not be able to have constant, or close to constant revolutions in the effective range of the engine operation, so that later we will not be able to easily transfer this to the engine operation time. "I sell BMW 520, run 3000 hours, 7000 hours before overhaul" - forget it.

Y-value - average speed of movement

Hours at constant rpm would be ideally accurate to estimate the resource - in fact, this is the number of perfect revolutions since the start, but they do not fit - let's count the mileage in kilometers traveled. The range of revs required is wide - and there's nothing you can do about it. Will it be easier with the mileage? Alas, we also have a gearbox with a main gear pair. It allows torque and RPM to be converted into actual speed over an even wider range. The range of operating speeds may differ not by an order of magnitude, but by two - theoretically, from units of km / h to a couple of hundred. It only saves that from the point of view of the resource, we consider the range of average speeds, which, in turn, are limited not so much by the box as by the operating conditions. Of course, taking into account the real speeds of movement and the constancy of the gears used in this case, the very fact of the presence of the box is not so important - the real speeds are far from the available 1-250 km / h. Most likely, for city conditions, these are the ranges of average speeds of 20-30 km / h, for the highway - 80-90 km / h and higher. The difference is only 3-4 times. It's not that scary anymore. Here we again came to the concept of "engine hours". A typical situation: the engine runs for an hour - we drive 20 km pushing in a traffic jam. The engine runs the same hour on the track - the car has driven 90 km. For 3-4 years, a "city dweller" comes across 35-40 thousand km. A traveling car in the suburbs - all 150-200!

By engine hours, it will be the same. Is it possible that each kilometer of the "city" in terms of resource will be equal to 10 kilometers of the "highway"? Why so much? Let me remind you that "city hours" are much worse from all points of view. For many Asian and American cars, it is negligible. It is even possible that it is almost imperceptible. For the Germans, with pronounced "ecological" regimes, the dependence is much more pronounced. Having "planted" ring plugs for a year, you start the mechanism for calling overhaul not due to wear, but, for example, due to oil consumption ... This is not an accelerated reduction in the resource as such, it is an emergency unscheduled repair that occurred as a result of an operating mode not foreseen by the manufacturer. The engine does not so much wear out faster as it starts to work in a freelance mode. Such operation is no different, for example, from constant overheating, or running the engine without lubrication ...

Z-value - everything else

Here we have both the service (what is poured and when it is poured) and the climate (do you not start the car every day at -40?) And the peculiarities of the operating mode - "it is operated only in summer, the third car in the family." Interestingly, when you come to the dacha once a year, is it not surprising, for example, that the gate creaks? And that the car stands idle for 8 months - probably only benefits - kilometers on the odometer do not grow - "original mileage".

What we have in practice, actually encountered options for pre-sale inspections (for example, BMW engines):

1.Relatively large Russian mileage for its year is conventionally above 30 tkm per year. As a rule, cars are in close to perfect technical condition for the engine and automatic transmission, in full accordance with the laid down resource. Even completely problematic engines N46 and N52 at the age of 4-5 years and with a shocking Russian average mileage of 150+ tkm can be in satisfactory, good or even almost perfect condition. The criterion for a rough assessment for the reader I can offer is the following - 2.1 and 0 liters of oil consumption per 10,000 km, respectively. "10,000 km", in this case, means urban. Here "mileage" works honestly - "wear and tear". These 150 thousand mileage without constant traffic jams (and how else will you manage to hit them ?!) are approximately equal to 20-30% of the total resource before the planned overhaul - I have seen references to the "traveling" N46 and N52 with runs of 400-500 thousand. I wouldn't be surprised if there are more. If the owner for some reason (sometimes it happens) also guessed with oil - the car generally differs little from a purely "European". Once the owner of a "Russian" N46 motor with a "no problem" mileage above 300+ km or even more clung to me. Like "you write nonsense about the resource N46". As always, a person, based on his own example, has drawn a picture of the world for himself. On the fifth round of communication, interesting details became clear, here I would rather give quotes, while preserving the author's style:

"even if you believe the bot computer, then my average is 43, work is mostly evening-night, usually I go out no more than 10 hours and hardly stand still. Life during the day, I serve the car myself. During my shift, I run about 350 km. Your calculations are wrong !!! .

And here's another, I can't resist, I always write about the "Moscow races" ... That is, I am mistaken in twins, here is the proof:

"In Moscow. On average, I got from 90,000 to 110,000 per year. There was little track in the summer only to the dacha, and then halfway it was Moscow and traffic jams with dergatny ..."

On average, 90-110 thousand km (!) Came out per year (!). Keyword - in Moscow. Probably, it was understood that in the term "in Moscow" I include the influence of geographic location on the structural composition of the engine metals. But that's not all: 90-110 tkm and ... "there are not enough tracks"... That is, it is considered, obviously, some more difficult to understand mechanism of the geographic connection of the place ("track") and the state of the motor. Well, what is 90-110 tkm (let's take the average - 100,000 km) in terms of driving hours?

A good average speed of real movement "in Moscow" on weekdays - something about 20-25 km / h. 100,000 km for 25 - 4000 driving hours. 4000 engine hours. By the way, by the way, this is about 10 oil changes per year (!) And ... 11 hours a day behind the wheel.

Here either "In Moscow" or "my average 43 km / h", "highway" and "90,000 to 110,000" per year. I will willingly believe that even with real pushing in traffic jams in the mornings and evenings and relatively free movement only in the city in the daytime and in the evening at an average speed of 40-45 km / h, the internal combustion engine will be in excellent condition. But the mechanisms for achieving this goal will be somewhat different here: the almost constant operation of the motor, frequent scheduled oil changes- even if you do it every 25 tkm - This is a 4-fold upgrade of the most important ICE health fluid!

2. Example two: the mileage is below the average - 15 tkm per year or less. Yes, and "the girl went". When they say that, they mean, obviously, that it was not a young man who drove - he did not press the gas, but he didn’t flatten the bumpers on the curbs, he didn’t knock down the parking posts. In other words: the rings were planted with a reduced intensity of operation. The result is oil-filled cylinders in cars with internal combustion engines from the category of problematic ones (for example, all the same N52 and N46) on the runs already 30-40 thousand km and about. Consumption of 1 liter per 1500-2000 km of escape - the state is exactly "pre-capital". Another 1.5-2 years and there will be a "complete program" of repairs: the cost of the car will unexpectedly increase by 180-200 thousand rubles and even more. For 3-4 year old "svezhak" it is 20-25% of the cost of the car upon purchase.

3. Examples "average" and do not consider exceptions - about the first, there are already publications in the first blog post. About the second, it is worth talking considering each specific case - there is always an explanation.

They are simple: mileage may have very little to do with the real state of the engine and the car in general. Moreover, a lower mileage, other things being equal, can be an aggravating factor for the actual condition of the motor. A mileage of 30-40 thousand kilometers is most likely optimal for an engine aged 1-2 years. And for a 5-6 year old car, it may not be a reason for joy, but a big problem. Having overpaid 10-15% of the cost for a car with a low mileage for your age, prepare the same amount to eliminate the consequences of this low mileage. It is strange to read, for example, messages like "the car is in excellent condition, the mileage is very small, though I add something for 2-3 thousand liters ..." - what is the consolation in this case? Figures on the tidy? The motor is coughing up blood, but the blood test is in order? A car idle for 1-2 years, even with periodic engine starts, can lead to complete blocking of the rings - a drop in compression to zero in all cylinders. I personally examined several such cases. "The car must drive." This is a necessary condition for maintaining its nominal performance.

The decision to buy a used car does not come from a good life. Therefore, you always want to find a well-groomed, unbeaten and low-mileage specimen. But should high mileage always be embarrassing?

Everything is fair

A car purchased for fair ownership almost always has a fairly specific scenario for its use. On weekdays, these are home-work trips, on weekends - a summer cottage and a supermarket. In the summer (and not only), vacation trips can be added. How much can you roll in this mode? At most 20 thousand km per year. And even 10-15 thousand. By the time the decision is made to sell and appear on the secondary market, such a car will have a mileage of about 70 thousand kilometers. But what kind of mileage will it be?

A daily commute to and from work is two cold starts of the engine, warming up to operating temperature while on the move and pushing in traffic jams. And all this on a run of 10-20 kilometers. In a word - an extremely unfavorable mode, both for the engine and for the transmission. The internal combustion engine is a capricious unit. For him, the most favorable working conditions are constant and not very high speeds with a constant load. In all other cases, he definitely doesn't like something.

Cold start and warm-up to operating temperature

Whatever the manufacturer of lubricants promises, but when the engine starts, there is little oil in the friction pairs. This amount of oil is at least enough for the first few tens of revolutions, until the oil pump starts supplying lubrication to the most distant corners of the engine. But the oil remains cold for 2-3 minutes after starting, which means it is thick. And reluctantly enters the gaps.

The heating gaps themselves are also not optimal. After all, their dimensions are selected by designers based on the operating temperature. While the engine is cold, the gaps are relatively large, which means that shock loads are more likely in them, and in the cylinders an increased gas breakthrough into the crankcase is inevitable. If we start moving immediately after starting the engine (as is recommended by almost all manufacturers, relying on the ecology that is fashionable today), then these shock loads become even greater. And an excess of crankcase gases oxidizes engine oil more strongly. And the colder the climate, the more relevant and essential all of the above factors are.

Acceleration, braking and idling in traffic jams

What happens even on a warm engine when you suddenly press the gas pedal? The following happens. We pressed the pedal, the electronics began to "rich" the mixture, the revolutions and the load increase, and the pressure and the amount of oil do not have time a little. The result is increased carbon formation due to the rich mixture and increased loads in friction units.

Gas discharge is not sugar either. Indeed, in this mode, the throttle valve is closed, and the intake vacuum is high. As a result, we have a slightly increased penetration of oil into the combustion chambers through the bushings of the intake valves, even with the oil scraper seals not yet worn out.

Well, long idle speed for modern gasoline engines is a separate topic altogether. Especially coupled with a sharp subsequent acceleration. When the electronically controlled thermostat keeps idle at 115 degrees, we press on the gas, the temperature in the cylinders rises, and the inertia of the cooling system does not allow us to cope with the sharply increased heat load. And then we brake sharply and again stand, and the thermostat again returns to its "eco-friendly" 115 degrees. And at this time, oil burns intensely on the red-hot piston rings that did not have time to cool down. As a result, the rings coke, lose their mobility, and the oil consumption rises to completely obscene values.

Do you still want to look for a low mileage car?

Of course, all of the above is some exaggeration. But when all these factors work together, then the trouble in the form of a smoking engine creeps up to 50 thousand kilometers.

Long-term driving on the highway

Kilometers in this mode wind up quickly, but with the wear of the engine and gearbox, everything is exactly the opposite. The established stationary mode of movement and operation of the motor is the most gentle in terms of wear and other misfortunes.

The oil pressure is constant and stable, and coupled with the absence of sharp changes in speed, we have an equally stable oil film between all rubbing parts with their practically zero wear. The mixture entering the cylinders is close to the ideal ratio of "gasoline-air", which means that it completely burns out without leaving carbon deposits. Moreover, soot accumulated in city traffic jams gradually burns out. The cooling system also works stably, removing excess heat from the cylinder walls and from the piston rings. The oil on them does not burn and does not coke.

Idyll? Almost. At least, long-haul tractors have mileage of a million kilometers or more. And on such a run, the motors and gearboxes are almost not worn out. And not only because of the low level of forcing, but just as a result of the above factors.

And now an example from personal practice. A dozen years ago, the zigzag of fate presented me with a surprise in the form of a right-hand drive device Honda Torneo (European counterpart - Accord). The car was four years old, "run-free" (Siberians and the Far East will understand) and with a range of ... 124 thousand kilometers. At a time when the market was full of offers with a mileage of 40-60 thousand. But the price was very, very different.

After the initial examination, intuition and experience suggested that, as they say, “we must take”. When I drove this car into a friendly "Honda" service for inspection and maintenance, my acquaintances were not at all surprised by the condition of the car, which can be described with the words "almost new". All parameters of the engine and automatic transmission were within the factory tolerances. Let me remind you: the mileage is 124,000 km! Having reeled in another 65 thousand in two years, I sold this "Honda" without a single repair intervention in it.

Of course, the infinite variety of operating conditions in specific conditions by specific people makes its own adjustments to all our theoretical calculations. Yes, and "high mileage" also has its limits, especially if a taxi car with real mileage of 300-400 thousand. But still, it is not in vain that the first place in the initial selection of a used car is exactly the year, and only then - the mileage.

Because some modern and high-tech 3-year BMW 320 with a mileage of 150 thousand will easily be in much better condition than a 5-year-old, but wound up 50 thousand. But we have not yet mentioned that after a run of 100-120 thousand they have already been replaced: a timing belt with rollers (or a chain), many suspension elements, and not only them. Therefore, when choosing a used car, do not immediately discard options with “over a hundred” mileage. But in any case, do qualified diagnostics - it will just show the true condition of the car.

Hello.

I drive a car mainly on the highway. what is the approximate ratio of wear and tear on an auto highway city? That is, 100 km of run in the city is harder for the author than on the highway. How long does it take to change oil and consumables?) What conditions are ideal for a city or highway

Evgeniy On the highway, consumption is less by about 20-30%. The absence of traffic lights, constant acceleration and deceleration, uniform movement at a constant speed reduce fuel consumption. In the "track" mode, the wear of the car is much less than in the city, therefore, it will take more. Consumables and oil should be changed according to the regulations of your car manufacturer.

Sasha Gorod, these are difficult operating conditions, see the service card and read the asterisks

Tags: Mileage is better on the track than on the city

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Gasoline consumption | Topic author: Wieslawa

Tell me what's the matter or what's wrong - my smiley is not eating childishly, namely 7.8l (92benz.) On the highway and 9l around the city, and if with a conductor, then generally tryndets !!! Total mileage exceeded 4200km

Ruslan (Gosdan) My consumption dropped after 10,000 km. And look at the guides on the front brake calipers, they are not lubricated from the factory and the pads constantly slow down the car.

Kostyan (Onllwyn) my locomotive is eating! the support is tired of cleaning! in general, somewhere around 10 in the city, and on the highway at a speed of 150-140, on average, it eats about 8 liters

Denis-Ivanovich (Azarel) Kostyan, what is the mileage? and up to how much on the average do you spin the engine? (maybe it depends on it)?

Kostyan (Onllwyn) Denis-Ivanovich, mileage 40,000, I spin it up to 6, but even when I drive to 3 in a quiet mode, it eats!

Marsel (Milborough) I have 5.2 on the highway at 120-140! 6.5-7 in the city!

Anton (Euphemia) grease the slide rails on the calipers, you will immediately feel the difference!

Elina (Markita) and how to lubricate these calipers)))

Ruslan (Gosdan) best imported CV joint grease

Yury (Kaisa) Good afternoon, the car eats a lot (about 11 liters in the city in normal mode), the officials say that there is no point in adjusting, like you need to flash your head, and the consumption will decrease by about 3-4 times! Tell me who knows about this head firmware? Does it work, otherwise it’s not cheap (3000r) I don’t want to pay money so easily!

Kirill (Gopa) Chip tuning is called. The prices are different, 3 r. Is still good.
This kind of firmware is a well-known thing and, most importantly, very useful and effective. The machine is not stitched for a long time, from different sources - about a couple of hours. There are several types of firmware, for example, sports (fuel consumption and liters from the car increase), well, or economy.

Oleg (Jahmal) I noticed that on 95 gasoline the consumption is noticeably less than 92. so I refuel 95 - it comes out cheaper

Seryoga (Shrila) lubricated the caliper with aerosol copper grease, liquidated it. After 15000 everything is fine. And the grease is like new

Viktor (Iyanna) people at what mileage it is better to lubricate the guides by 1, then I haven’t traveled yet, I want to go there for the first time to look and score myself.

Viktor (Iyanna) refueled 10 from the salon was enough for 80 km, now it seems less hawking

Seryoga (Shrila) Victor, as they say, the sooner the better

Anton (Euphemia) less than Zhiguli

Lena (Roseline) Victor, there is nothing to do at the first MOT if everything is OK !!! all the same, jambs climb out after the first one is closer to the second;))))

Natalya (Parmveer), by the way, at the expense of 95 gasoline. if I fill in 20 liters, I have enough of it for 5-6 days, it eats this gasoline very slowly ... but the same 20 and only 92 is enough for 4 days stably ..... when running in, the machine ate noticeably a lot. and after that everything stabilized .. now 11000 thousand km and everything is as it should be. small economy car ..;) :)

Anton (Euphemia) filled 92 gasoline 36 liters drove in a combined cycle in a traffic jam, sales were enough for 500 km. and 95 poured 36 liters, traveled in a mixed, again 500 km, drove in general, I did not feel the difference either in power or in economy. I refuel on Lukoil again 92

How often do you need to change the engine oil - Kolesa.ru

Jan 24. 2015 - City and highway ... The same mileage on the highway and in city mode is more than a fourfold difference in ... But the conditions are a little more difficult and the number of engine hours is higher, and it would be better to shorten this interval.

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such a mileage may indirectly indicate that the car was mainly operated along the highway, and this is better than in the city ...