The decision to buy a used car does not come from a good life. Therefore, you always want to find a car that is well-maintained, undamaged and has low mileage. But should high mileage always be a problem?

Everything is fair

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

A daily trip to work and back means two cold starts of the engine, warming up to operating temperature while already driving, and pushing in traffic jams. And all this on a run of 10-20 kilometers. In a word - an extremely unfavorable mode for both the engine and the transmission. Engine internal combustion— the unit is capricious. For him the most favorable conditions work is permanent and not very high revs with a constant load. In all other cases, he definitely doesn’t like something.

Cold start and warming up to operating temperature

No matter what the manufacturer promises lubricants, but when the engine starts, there is little oil left in the friction pairs. This amount of oil is at least enough for the first few tens of revolutions, until oil pump will not begin to supply lubricant to the most remote corners of the engine. But the oil remains cold for 2-3 minutes after start-up, which means it remains thick. And it penetrates into the gaps reluctantly.

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

Acceleration, braking and idling in traffic jams

What happens even on a warm engine when sharp pressing on the gas pedal? What happens is this: We pressed the pedal, the electronics begin to “rich” the mixture, the speed and load increase, but the pressure and amount of oil do not keep up a little. The result is increased carbon formation due to rich mixture And increased loads in friction units.

Discharging gas is also not sugar. After all, in this mode throttle valve closed and the inlet vacuum is high. As a result, we have a slightly increased penetration of oil into the combustion chambers through the bushings intake valves even if they are not yet worn out valve stem seals.

Well, long idling for modern gasoline engines- this is a completely separate topic. Especially coupled with the sharp subsequent acceleration. When the electronically controlled thermostat holds an idle of 115 degrees, we press the gas, the temperature in the cylinders rises, and the inertia of the cooling system does not allow it to cope with the sharply increased thermal load. And then we brake sharply and stand still again, and the thermostat again returns to its “eco-friendly” 115 degrees. Meanwhile, the oil burns intensely on the hot piston rings that have not had time to cool down. As a result, the rings become coked, lose mobility, and oil consumption increases to completely indecent values.

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

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

Long driving on the highway

Kilometers add up quickly in this mode, but with wear and tear on the engine and gearbox, everything is exactly the opposite. The established stationary mode of movement and operation of the motor is the most gentle from the point of view of wear and other misfortunes.

The oil pressure is constant and stable, and coupled with the absence of sudden changes in speed, we have an equally stable oil film between all rubbing parts with almost zero wear. The mixture entering the cylinders is close to ideal ratio“gasoline-air”, which means it burns completely, leaving no soot. Moreover, the soot accumulated in city traffic jams gradually burns out. The cooling system also works stably, removing excess heat from the cylinder walls and piston rings. The oil on them does not burn and does not coke.

Idyll? Almost. At least, mainline tractors have mileage of a million or more kilometers. And at such a mileage, the engines and gearboxes are almost not worn out. And not only for the reason low level forcing, but precisely as a result of the above factors.

And now an example from personal practice. A dozen years ago, a zigzag of fate gave me a surprise in the form of a right-hand drive Honda Torneo (European equivalent - Accord). The car was four years old, trouble-free (Siberians and Far Easterners will understand) and had a mileage of... 124 thousand kilometers. At a time when there were a lot of offers on the market with mileage of 40-60 thousand. But the price differed very, very significantly.

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

Of course, the endless 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 the car is from a taxi with actual mileage for 300-400 thousand. But still, it’s not for nothing that the first place in the initial selection of a used car is the year, and only then the mileage.

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

In advertisements for sale, it is difficult to find a car with a mileage of more than 150,000 thousand kilometers. After passing this magical milestone, almost any car immediately goes in search of a new buyer. After 2-3 years of operation, we see it on sale again... with approximately the same mileage. The cycle of mileage in nature sometimes takes on a bizarre appearance - a friend once showed me statistics he accidentally found - the history of publications of advertisements for the sale of a car he now owns over 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 above 100,000 km. A car with a mileage of “250,000 km” is automatically synonymous with “about to be scrapped.” The indicated mileage of 140,000 km, for a car about 20 years old, automatically makes it the number one candidate for the show.

I have already briefly addressed the topic of mileage several times from the point of view ICE resource in different articles. Many basic concepts The connections 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- operating time of the unit in the set mode is a more accurate value characterizing the resource. Let's say, the diesel generator has worked well at constant speed for 10,000 operating hours - we still repair it as planned, according to the regulations. The mode is so monotonous that the “resource” is obviously generated almost exactly according to the operating time - there will be no surprises. If we continue to operate it, the likelihood of failure increases. Most likely this was determined at the time of development of the unit. This is easy to predict - the engine operating speed is constant and amounts to 1500 rpm. The expected 10,000 hours of service life 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 “car” mileage, we get something like 1 million kilometers. When using standard (ordinary, not best, in in this case) materials - resource (mileage) sufficient for all possible economic needs. Approximately similar mileage is found in commercial vehicles - the operating mode of trucks is close to the “theoretically ideal” engine operating mode, not much different from a diesel generator.

For a car, unfortunately, this value is not very convenient. The problem is that there is no “established operating mode” here. There are too many unknown quantities to be “attached” to an objective characteristic of a resource, be it kilometers or engine hours.

Value X - inconsistency of revolutions

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

In return, however, we get wild absolute fuel consumption, a tendency to overheat - why does the engine need to turn 2000 rpm when idle - wasted fuel? You can force yourself not to rev the engine above 4000 rpm, but low revs, idle speed is more difficult to get rid of. Therefore, by eliminating the most harmful mode - the extremely ineffective and extremely useless “idling” in the region of 600-650 rpm, we got rid of many problems with the resource, but at the cost of extremely inefficient consumption of the energy received. If you don't spend money on repairs, you'll spend money on gasoline and fighting overheating. Unfortunately, we are postponing the option of “narrowing” the effective speed range to ensure stability in the resource estimate in engine operating hours - this is not economically profitable. Environmentalists will protest and refueling every 100 km will not suit you. We will not be able to have constant, or close to constant speeds in the effective range of engine operation, so that we can then easily translate this into the operating time of the engine. “I’m selling a BMW 520, mileage 3000 hours, 7000 hours before overhaul” - forget it.

Value Y - average speed

Engine hours at constant revolutions would be ideally accurate for estimating the service life - in fact, this is the number of revolutions completed since the start, but they are not suitable - let's count the mileage in kilometers traveled. The range of required revolutions is wide - and nothing can be done. Will it be easier with mileage? Alas, we also have a gearbox with the main transmission pair. It allows you to transform torque and revolutions into actual speed into even more wide range. The range of operating speeds may differ not by an order of magnitude, but by two - theoretically from a few km/h to a couple of hundred. The only saving grace is that, from a resource point of view, we are considering a range of average speeds, which, in turn, are limited not so much by the gearbox as by operating conditions. Of course, taking into account the actual speeds of movement and the constancy of the gears used, the very fact of having a gearbox is not so important - real speeds travel is far from the available 1-250 km/h. Most likely, for city conditions these are average speed ranges of 20-30 km/h, for highways - 80-90 km/h and higher. The difference is only 3-4 times. It's not so scary anymore. Here we again come to the concept of “motor hours”. Typical situation: the engine has been running for an hour - we drive 20 km, jostling in a traffic jam. The engine runs for the same hour on the highway - the car travels 90 km. In 3-4 years, a “city dweller” will hit 35-40 thousand km. A traveling car in the Moscow region - all 150-200!

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

Z value - everything else

Here we have maintenance (what they pour and when they pour it) and the climate (at -40 you don’t start the car every day?) and the peculiarities of the operating mode - “it’s only used in the summer, the third car in the family.” I wonder when you come to your dacha once a year, isn’t it surprising, for example, that the gate creaks? And the fact that the car sits motionless for 8 months is probably only beneficial - the kilometers on the odometer do not increase - “the mileage is original.”

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

1.Relatively large Russian Mileage for its year is conditionally higher than 30 tkm per year. As a rule, cars are close to ideal technical condition on the engine and automatic transmission, in full accordance with the intended resource. Even completely problematic N46 and N52 engines aged 4-5 years and with mileages of 150+ tkm shocking the Russian average can be in satisfactory, good or even practically perfect condition. I can offer the following rough assessment criterion for the reader - 2.1 and 0 liters of oil consumption per 10,000 km, respectively. "10,000 km", in this case, means urban. Here the “mileage” works honestly - “for wear and tear”. These 150 thousand mileage without constant traffic jams(how else will you have time to run over them?!) approximately equal to 20-30% of the total resource before planned overhaul - I have seen references to “traveling” N46 and N52 with mileages of 400-500 thousand. I wouldn't be surprised if there are more. If the owner for some reason (this happens) also guessed right with the oil, the car generally differs little from a purely “European” one. Somehow I was approached by the owner of a “Russian” N46 engine with a mileage “without problems” of over 300+ km or even more. Like “you’re writing nonsense about the N46 resource.” As always, a person, based on his own example, developed a picture of the world for himself. On the fifth round of communication, it turned out interesting details, here I’d rather give quotes, preserving the author’s style:

"even if you believe the bot computer, my average is 43, my work is mostly evening and night, I usually go out for no more than 10 hours and hardly stand still. Life during the day, I service the car myself. During my shift I cover about 350 km. Your calculations are not correct!!! .

And yet, I can’t resist, I always write about “Moscow runs”... That is, I’m double mistaken, here’s the proof:

“In Moscow. On average, I earned from 90,000 to 110,000 per year. There weren’t many routes in the summer, only to the dacha, and then halfway there it’s Moscow and the traffic jams are rough...”

On average, there were 90-110 thousand km (!) per year (!). Keyword - in Moscow. It was probably meant that in the concept “in Moscow” I include the influence of geographic location on the structural composition of engine metals. But that’s not all: 90-110 tkm and... "there are not enough tracks". That is, we are obviously considering some other more difficult to understand mechanism of the geographical connection between the place (“route”) and the state of the motor. Okay, what is 90-110 tkm (let’s take the average - 100,000 km) in terms of driving hours?

Good average speed real movement“in Moscow” on weekdays - something around 20-25 km/h. 100,000 km for 25 - 4000 hours behind the wheel. 4000 engine hours. By the way, this is about 10 oil changes a year (!) and... 11 hours a day behind the wheel.

Here it’s either “In Moscow”, or “my average is 43 km/h”, “highway” and “90,000 to 110,000” per year. I will readily believe that even in real jostling in traffic jams in the mornings and evenings and relatively free movement only in the city during the day and 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: practically Full time job motor, frequent planned replacements oils- even if you do this once every 25 tkm - this is a 4x update of itself important fluid for the health of the internal combustion engine!

2.Example two: mileage is below the statistical average - 15 tkm per year or less. Yes, and “there was a girl driving.” When they say this, they obviously mean that the driver was not a young man - he didn’t press the gas, but he didn’t squash his bumpers on curbs or knock over parking posts. To put it another way: the rings were planted in a targeted manner - with a reduced intensity of operation. The result is oil-filled cylinders in cars with internal combustion engines from the problem category (for example, the same N52 and N46) at mileage of 30-40 thousand km or so. Consumption of 1 liter per 1500-2000 km of escape - the condition is exactly “pre-capital”. Another 1.5-2 years and there will be a “full program” of repairs: the cost of the car will unexpectedly increase by 180-200 thousand rubles or even more. For a 3-4 year old “fresh” car this is 20-25% of the purchase price of the car.

3. Examples are “average” and I don’t consider exceptions - about the first ones, there are already publications in the first blog post. About the latter, it is worth talking about considering each specific case - there is always an explanation.

They are simple: mileage can have very little to do with real state motor and car in general. Moreover, lower mileage, all other things being equal, can be an aggravating factor for the actual condition of the engine. A mileage of 30-40 thousand kilometers is most likely optimal for an engine that is 1-2 years old. And for 5-6 summer car may not be a reason for joy, but big problem. Having overpaid 10-15% of the cost for a car with low mileage for its age, prepare the same amount to eliminate the consequences of this low mileage. It’s strange to read, for example, messages like “the car is in excellent condition, the mileage is very low, but I add something like a liter for 2-3 thousand...” - what is the consolation in this case? Numbers on the dashboard? The engine is coughing blood, but the blood test is in perfect order? Idleness of the car 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 necessary condition maintaining its nominal performance.

Hi all.

I'm going to passenger car mostly along the highway. What is the approximate wear ratio for a car, highway, city? That is, 100 km of driving in the city is harder for the author than on the highway. How often do you change the oil and consumables?) what conditions are ideal for the author - city or highway

Evgeniy  On the highway, consumption is approximately 20-30% less. Lack of traffic lights, constant acceleration and braking, uniform motion reduce fuel consumption at a constant rate. In the "track" mode, the wear of the car is much less than in the city, and therefore it will last longer. Consumables and oil should be changed in accordance with the regulations of your car manufacturer.

Sasha  City, this difficult conditions operation, see the service card and read the stars

Tags: Mileage is better on the highway than in the city

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Gasoline consumption | Topic author: Wieslawa

Tell me what’s wrong or what’s wrong - my smiley eats not like a child, namely 7.8 liters (92 petrol) on the highway and 9 liters in the city, and if with air conditioning, then it’s generally a mess!!! Total mileage exceeded 4200 km

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

Kostyan (Onllwyn)  I have a steam locomotive! I'm already tired of cleaning the calipers! 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 how long do you rev ​​the engine on average? (maybe it depends on this)?

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

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

Anton (Euphemia)  lubricate the guides on the calipers, you will immediately feel the difference!

Elina (Markita)  what to lubricate these calipers)))

Ruslan (Gosdan) is the best imported lubricant for CV joints

Yury (Kaisa) Good afternoon, the car consumes a lot (in the city in normal mode about 11 liters), the officials say that there is no point in tuning, like you need to flash the 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 (3000 rubles) I don’t want to pay money so easily!

Kirill (Gopa)  It’s called chip tuning. The prices are different, 3 t r is even divine.
This kind of firmware is a well-known thing and, most importantly, very useful and effective. The machine does not take long to flash, from different sources - about a couple of hours. There are several types of firmware, for example sport (fuel consumption and liters per car increases), or economy.

Oleg (Jahmal) I noticed that with 95 gasoline the consumption is noticeably less than 92. So I fill up with 95 - it turns out cheaper

Seryoga (Shrila) lubricated the calipers with aerosol copper grease Liquid Moyli. After 15,000 everything is fine. And the lubricant is like new

Viktor (Iyanna)  people, at what mileage is it better to lubricate the guides? 1 I haven’t gone yet, I want to go there for the first look and score it myself; doing everything myself allows me to do specialties

Viktor (Iyanna)  10 fuel from the cabin was enough for 80 km, now it seems to eat less

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

Anton (Euphemia)  less than on a Lada

Lena (Roseline)  Victor, there’s nothing to do at the first maintenance if everything is ok!!! all the same, shoals come out after the first, closer to the second;))))

Natalya (Parmveer)  by the way, yes, about 95 gasoline. if I fill 20 liters, it lasts me for 5-6 days, it eats up this gasoline very slowly for me... but the same 20 and only 92 is enough for 4 days consistently..... during the run-in, the car ate noticeably a lot. and then everything stabilized.. now 11,000 thousand km and everything is as it should be. small economical car..;):)

Anton (Euphemia)  filled with 92 gasoline 36 liters and drove to mixed cycle in a traffic jam the sales were enough for 500 km. and 95 filled 36 liters, drove mixed again for 500 km, in general I didn’t feel any difference in power or economy. I refuel at Lukoil again 92

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

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