How To Break In A New Car Engine

by | Apr 6, 2020 | News | 0 comments

Breaking in a new car is an exercise that’s been encouraged by car companies for years. It’s a mix of precautions, driving techniques and maintenance jobs, that are in the long run meant to help lengthen your car’s life-span.

Would you like the engine parts to settle in and begin working together correctly! Obviously! This is why auto producers provide recommendations instructing new car owners to maintain and drive their brand new cars in a particular way for a certain time period.

Due to developments in engineering, the need to break in brand new automobiles has been cut down tremendously recently. Car manufacturers these days use a lot more advanced oils, more sophisticated casting methods and more powerful components for the engine parts so that they don’t have to be run-in like they once were in past times. Nevertheless, you may still find lots of car manufacturers suggesting motorists to practice extreme caution throughout what has typically been regarded as the breaking-in phase. The main reason they still issue these suggestions is to stop any flaws that may possibly occur from an intense style of driving and incorrect car upkeep for the initial couple 100 miles.

  • What is the engine break-in of a new car, and what are its types
  • Why do I need a break-in engine of a new car
  • How to run in a gasoline engine in a car
  • What are the features of running a diesel engine

In modern cars, the achievements of technical thought and the aesthetics of external forms are combined, so new cars can not leave anyone indifferent, causing admiration for the look of their shiny and original bodies. Despite the fact that all units and engine parts have just been made, engine break-in of a new car is required. Why is this needed! Of course, the car will ride without break-in, but all moving and rubbing elements of the engine, transmission and chassis should be run in, rubbed against each other. This will make it possible to operate the car more confidently in the future, its uptime will increase, and the probability of breakdowns will decrease.

Types of engine break-in of a new car

The engine of the new car must not be 100% loaded until all the parts are rubbed against each other. Any mechanisms in which there are moving, rubbing parts need a break-in. Moderate load during this period allows all nodes in the soft mode to take an ideal position in relation to each other, without experiencing increased voltage.

The manufacturing technology of automobile engines includes their mandatory run-in in the factory. Naturally, the question arises, is it necessary to break in the engine of a new car! Dealers of many well-known automobile brands insist that it is not necessary to run the car in, because everything you need has already been done at the factory. That is, the buyer can operate his new car in any mode and in any conditions.

But this statement is contrary to the instructions for the car. In them (even to the most prestigious German brands) it is recommended that the first 1,500–2,000 km be observed to respect the gentle operation mode. Thus, we are talking about running in the engine of a new car.

The procedure for lapping engine components, which is carried out at the factory, is called commissioning (enginebreak-in). In the future, the mechanism needs a run-in (enginerun-in).

Run-in is carried out for the engine not only of a new car, but also in the event that any repair was carried out. Understanding the meaning of this procedure is not difficult. Any metal parts have microscopic roughness. During friction in the working mechanism at high temperature, these irregularities are smoothed out, and metal dust and chips are washed off with oil.

Also, during the running-in, the compression and oil rings are rubbed. They are in close contact with the walls of the cylinders, with moderate load during initial operation, their shape is more streamlined.

Due to the gentle running-in mode, all engine parts occupy an optimal position, as a result of which the load on the power unit of the engine is reduced. All this allows the motor to work out the full term for which it was designed by its creators.

Running in the engine of a new car (or after repair) is performed in several ways.

  • Using a break-in stand

Service stations are equipped with similar stands. They perform cold engine break-in after major repairs. At the same time, the engine itself does not work, only its components move. A similar method is used for both diesel and gasoline engines.

  • The engine removed from the car is placed on the break-in stand.
  • Antifreeze and oil are poured into the engine.
  • The crankshaft is driven by an external electric motor.

The engine break-in of a new car begins with the smallest turns, while the speed of rotation of the electric motor and the entire process is controlled by a computer. The computer collects data from sensors connected to the main components of the engine. In the process, in accordance with a given program and sensor readings, the rotation speed of the electric motor changes. At the same time, the set temperature is maintained, eliminating engine overheating. On this basis, the run-in is called cold.

  • Running in by towing

Running in by towing

Running in the engine of a new car can be done without the use of special equipment STO. To do this, using a rigid coupling, the car is attached to the towing vehicle, the movement along the highway is performed in third gear.

It is necessary to unscrew the candles from the engine of the new car, set the gear lever to the neutral position. Towing is done within an hour. At this time, from the rotating wheels, the forces are transmitted to the remaining nodes of the new engine, as a result of which they gradually grind to each other. In the process of towing, it is very difficult to control the heating temperature of the motor, so this method is not ideal for running in.

  • Hot run

This method is an alternative to cold running. The procedure can be carried out at the stand, while the motor removed and installed on the stand runs idle for 3 minutes. Then they give him the opportunity to cool, and then turn it on again. The cycle is repeated three to four times, then the engine cools down for 40 minutes.

Throughout the process, it is very important to maintain the engine temperature no more than 80 degrees. The motor must not be allowed to overheat, because of this some parts are able to deform. As a result, instead of running in, the whole mechanism will fail. Therefore, intervals for cooling the engine are very important.

  • Cautious movement on the highway

Lapping the motor components on the stand and using towing, of course, requires certain additional efforts and costs. Therefore, most often the engine break-in of a new car is carried out naturally in the process of careful driving. In this case, it is necessary to observe several rules, which will be discussed below.

Why do I need a break-in engine of a new car

Despite the fact that the engines of modern cars are made from high-quality components, break-in is still inevitable. Otherwise, increased loads on the new motor at the very beginning of operation will lead to the fact that the resource of the unit will be significantly reduced.

A large load on the engine occurs during a flash of rich mixture in the cylinder, when the piston moves slowly downward. This is not the same as high revs. Such conditions are created when the car moves uphill at a speed of 60–70 km / h in fifth gear (or at a speed of 40–50 km / h in 4th gear) when the gas pedal is depressed.

Why do I need a break-in engine of a new car

In this case, an outbreak of a rich mixture creates significantly greater pressure on the piston in the cylinder itself, when compared with the combustion of a lean mixture. Therefore, the pressure in the joints of the main and connecting rod bearings will be increased. In addition, the piston, pushed by the connecting rod arm, is pressed against the cylinder wall with a greater force with lateral displacement. Such repeatedly repeated movement leads to the fact that in older engines that have exhausted their life, the cylinders acquire an elliptical shape.

At the very beginning of the operation of the unit, the main and connecting rod bearings have a rough surface, which is easy to see under a microscope. This means that the bulges on the liner and neck will come into contact at some point. Excessive friction is prevented by an oil film between the parts. But if the load on the engine increases, then the pressing force will increase, and the oil film will simply disperse.

As a result of dry friction on one of the surfaces (usually on the liner, because it is softer than the steel or cast-iron neck of the crankshaft) a burr is formed. In the course of further operation, the defect will increase, which will result in engine failure and the need for overhaul.

In the process of running in the engine of a new car, the cylinder-piston group (CPG) is also rubbed. During this period, the surface of the cylinder is polished by rings. The design of the engine initially provided for a special abrasive treatment of the cylinder walls – a Khan grid. Microscopic roughness contributes to oil retention, which eliminates dry friction when the rings slip on the inner surface of the cylinder.

When the piston moves, a lateral force is created that presses the piston against the cylinder wall. It increases with increasing load on the CPG. Until the mirror on the cylinder wall is rubbed (initial stages of operation), the piston can be pressed so tightly against the side surface that the oil film between the ends of the compression rings and the honed wall will be torn. As a result, burrs will appear on the walls, which will lead to a decrease in compression and engine power.

With moderate load and gentle operation, the lateral displacement of the piston is small, and the polishing of the mirror occurs evenly.

During the break-in period, the main task is to prevent the engine from overloading, while its rotation speed does not play a big role. Engine speed during the break-in of a new car is much less important than the load. So, a high load at 2,000 rpm will have a much worse effect on the state of the unit than the mode of operation with a minimum load at 3,000–4,500 rpm. If the car is standing, then the engine can run at high speeds, since there is no load at idle.

The engine break-in of a new car is carried out in several stages, while there are certain rules that allow the entire process to be performed optimally.

Before proceeding directly to the run-in, you need to perform preparatory steps:

  • Using a dipstick, check the oil level in the motor (it should be between the upper and lower marks on the dipstick).
  • Check that the brake and coolant levels in the systems are correct.
  • Make sure that the tire pressure is correct.
  • Inspect the main elements of a new car, make sure that there is no leakage of process fluids – lubricants and others.
  • Pour high-quality fuel into the fuel tank.

Safely run the engine of a new car will allow the following rules:

  • Long operation of the unit at idle is not allowed.
  • It is necessary to monitor the speed and engine speed, smoothly and timely shift gears. The table of speeds corresponding to the gears is given in the car manual.
  • During the break-in period, the maximum number of engine revolutions is not allowed: the threshold value for gasoline engines is 3,000 rpm, and for diesel engines the recommended range is from 1,200 to 2,500 rpm.
  • An increased load on a new engine cannot be allowed, which occurs, for example, during prolonged movement downhill or towing other vehicles.
  • Braking and acceleration maneuvers should be performed very smoothly.
  • The traffic mode within the city is not suitable for normal running-in. It’s best to choose an even highway.

How many km should the engine run in a new car

On this occasion, the opinions of experts differ, but nevertheless they are unanimous in that the most important thing in running-in is how the car travels the first one thousand five kilometers. It is during this period that all the prescribed rules must be carefully observed, and the car should be operated with maximum care. In the future, some concessions can already be allowed.

How long does the engine run in a new car last! Experts recommend running into 3 to 5 thousand kilometers in run-in mode. It should not be limited to the minimum mileage, because the greater the distance your car will go in the mode of careful operation, the more reliable and longer its systems will subsequently work.

If the manufacturer did not indicate a break-in period in the operating instructions of your car, then you should adhere to the gentle mode at least for the first thousand kilometers.

Proper engine break-in of a new car: step-by-step instructions

The motor is the main unit of the car, for which the break-in is especially important, because all its elements require grinding. The engine break-in of a new car is best carried out in several stages.

Stage 1. Mileage is approximately 500 kilometers.

During this period, it is necessary to ensure the minimum load on the transmission and engine, and this can be achieved with the most uniform movement. This mode is easy to observe on a suburban highway. In this case, the first 50 km need to go in third gear at a speed of 40-50 km / h. Then you can accelerate to 70 km / h and continue driving in fourth gear for another 100-150 kilometers.

In the future, having traveled 100 km, you can increase the speed by 10 km / h, continuing to move in fourth gear. In the next hundred kilometers you need to accelerate again by 10 km / h. Thus, by the end of your route, the car will reach a speed of 90-100 km / h. It must be remembered that it is impossible to accelerate quickly, and climbing uphill is also contraindicated. If such conditions could not be avoided, then it is necessary to minimize the load on the engine. To do this, smoothly slow down and lower the gear.

Stage 2. We drive the next 500 kilometers.

This stretch of road on a new car must be driven at a speed of 100-120 km / h, using only fifth gear. Check the engine speed – the maximum value must not exceed 3,000 rpm. Long steep climbs are also undesirable on this stretch of track. If they have met, then they should be overcome in low gear – fourth or even third.

Stage 3. The next section with a length of 500 km can also be driven at an increased speed of 130–140 km / h. During acceleration, the engine speed can reach up to 3,500 per minute. It is better if this section of the road will do without overcoming the slides. If this can not be avoided, then we pass them in a low gear, the fifth should not be included categorically. The engine should not be braked all the way.

Stage 4. Mileage is 2,000 kilometers or more.

On this stretch of the road, the car can easily cope with small deviations, moving in fifth gear. The speed should be maintained at the same level of 100-110 km / h. Moving on a flat area at a speed of 80–90 km / h, you can not switch from fifth gear. When accelerating from a stopping point and when changing gears, make sure that the number of engine revolutions per minute does not exceed 4,000.

In the driving environment, there is a misconception that the engine idling is a gentle mode. For the normal functioning of the engine, it is necessary that all its friction units are constantly lubricated with oil, as a result of which dry friction is eliminated. This is only possible if the engine speed is at least 1,200 per minute. Under such conditions, the desired oil pressure is achieved and a protective film is created on the moving parts.

Therefore, when idling, the oil pressure is low and the lubrication of the engine components is insufficient, which leads to increased wear of the rubbing pairs. That is, you need to use idle only for warming up the engine for 2-3 minutes.

Attention! Oil is poured into the power unit of the vehicle by the manufacturer, it should not be drained immediately. Oil change is carried out after engine break-in of a new car.

If the new car is equipped with an automatic transmission, then it is run-in according to the same scheme as in the case with a mechanical transmission. But there are some nuances that relate to the manipulation of an automatic gearbox (automatic transmission).

Engine break-in of a new car with automatic transmission

The rules for handling an automatic transmission when running in the engine of a new car are as follows:

  • Before starting the movement, you must turn on the engine and warm up the system. This is necessary so that the oil in the transmission reaches the optimum consistency.
  • It is impossible to sharply press the gas pedal all the way, that is, the kickdown mode is not allowed.
  • Wheel slippage should not be allowed, even a small one.
  • When driving, do not use a neutral gear. In this case, the oil pressure will drop and the “engine” will start to heat up, as a result of which the load on the planetary mechanism will increase.
  • Running in a new car should not be carried out in the city, since it will not be possible to avoid frequent and sharp changes in the rhythm of movement, as a result of which the automatic transmission can be seriously damaged.
  • After a complete break-in of the engine of a new car, it is worth performing an oil change in an automatic transmission.

Handling an automatic transmission during the engine break-in period of a new car should be more gentle than with a manual transmission. This is understandable, since the first is a more complex mechanism, therefore, its repair will cost much more.

Features of running in a diesel engine of a new car

You can meet the opinion that diesel engines do not need to be run-in at all, because they are stronger, more reliable than gasoline engines, and operate at lower speeds. Such a statement is groundless and even erroneous.

The designs of internal combustion engines (ICE), although they undergo some improvements over time, are not fundamentally changed. The power unit is still assembled from many elements that interact with each other in the process. Therefore, despite the new advanced technologies, it is not yet possible to completely avoid the natural wear and tear of engine components as a result of friction.

Features of running in a diesel engine of a new car

That is, there is no doubt that running in the diesel engine of a new car is also necessary. How many kilometers does a car need to travel in gentle mode! Run-in run is several thousand, during which the engine and other components of the car should not experience increased loads. As a result, all the conjugated elements will be rubbed in, they will occupy the optimal position, which will allow the new car to work out the deadline.

Since rubbing elements are present in any type of engine, and a lubrication system is provided for their normal functioning, the break-in principle for gasoline and diesel engines is approximately the same.

The initial stage of operation of a vehicle with a gasoline or diesel engine is based on maintaining the optimal pressure in the lubrication system and at the same time ensuring a minimum load on the engine and transmission. For a diesel engine, this mode is created when the crankshaft rotates 1,100–1,300 per minute, while maintaining the optimum pressure of the engine oil, therefore, lubrication of parts is carried out in the best way.

During break-in, the specified number of revolutions must not be allowed to decrease. This is fraught with the fact that the pressure in the oil system will be low and the oil film will be too thin on some rubbing vapors. As a result, the surfaces overheat, which will lead to premature wear of the parts. The same thing happens when the engine is idling. Therefore, during the break-in period, the diesel unit is only warmed up by idling.

Recommendations for running a new diesel engine in different manuals and instructions are slightly different. In addition, experienced auto mechanics can also provide some useful tips. Consider the main points to understand how to properly run in the diesel engine of a new car.

  1. It is best to run-in outside the city, otherwise you cannot avoid sharp braking, downtime in traffic jams and at traffic lights, during which the engine will idle. Outside the city, not only you will feel more confident and will achieve the desired driving mode, but also will not create problems for other participants. It is optimal to choose a route over a distance of 250 km, then taking into account the return road, you will overcome the first run-in stage of 500 km.Break-in engine of a new car
  2. The most responsible approach to running in should be taken at the first thousand kilometers. At this stage, it is forbidden to tow other vehicles, and also do not load the cabin, any passengers will be superfluous.
  3. Before starting the movement, you need to warm up the engine in idle mode to 20-30 degrees. The diesel engine is able to warm up well on the go, so you should not drive it for a long time beforehand.
  4. After the engine has warmed up, you need to move very smoothly. On engines with a manual gearbox, at the very beginning of the movement, you cannot engage a gear above the second. For “engines” you just need to block transfers from the third and higher.
  5. Until the engine warms up to operating temperature, it is necessary to maintain a reduced speed and speed. These parameters should nevertheless provide a normal oil pressure in the system. If the diesel engine runs in low gears, then the crankshaft speed must be kept in the range of 1,200–1,500 per minute.
  6. As soon as the engine warms up to normal, you can increase the speed. For vehicles with a manual gearbox, the fourth and fifth gears should not be used, and the engine must be locked to prevent shifting above the third gear. The engine break-in of a new car is carried out in a gentle mode, avoiding exceeding the load on the motor. Also, do not brake the engine. Using a brake system to reduce speed will allow you to rub the pads. Climbing uphill cannot be performed in high gear with the accelerator pedal depressed. It is also not recommended to drive for a long time without changing speed.
  7. When purchasing a new car, ask the seller what engine and transmission oil is used in the car’s systems. Similar information needs to be obtained with regard to brake fluid and antifreeze. Just in case you need to have about 3 liters of engine oil and one liter of other technical fluids: antifreeze, gear oil, brake fluid, distilled water, power steering fluid (if such a system is available in your car).
  8. On the highway you can move at speeds up to 80 km / h in 4th gear. If there is a rise, then you need to slow down and lower the gear. If the car is equipped with a manual gearbox, it is necessary to shift gears in a timely and very smooth manner. Using an automatic transmission, eliminate kickdown during break-in. Every 15–20 minutes, the engine speed should be changed in the range from 1 800 to 2 200–2 500 (these values ​​are applicable for a diesel engine).

Over a stretch of the path of 250 km, it will be necessary to stop twice on a flat platform and turn off the engine. After a few minutes, you need to check the level of engine oil and other technical fluids. It is also good to ask about tire pressure.

tire pressure

If the design of an automatic transmission allows you to control the oil level, then this item is also included in the list of actions during a stop. Before checking the fluid level in the cooling system, you need to make sure that the motor has cooled sufficiently. If the motor does not overheat in the direction of travel, and the coolant level is clearly visible from the outside by the mark, then there is no need to remove the cap of the expansion tank. When controlling the level of technical fluids, pay attention to their other characteristics – color, smell. Inspect components and assemblies for leaks.

After you have checked everything, with the hood open, turn on the engine and listen for any extraneous noise. Make sure that the electrical equipment is working. It is advisable that such a regulation of inspections be carried out while the engine break-in of a new car passes over the first thousand kilometers.

This distance is the most important step for engine break-in. The car must pass it in a gentle mode, while you must strictly adhere to all established rules. In the future, you can gradually increase the load on the motor.

Experienced auto mechanics believe that for a full break-in a new car with a gasoline or diesel engine should cover 10,000 km. Moreover, there is an opinion that the piston rings are completely rubbed against the cylinder walls only after a mileage of 30,000 km. This is due to the fact that it is by this time that a cylinder mirror is formed. That is, any car owner needs to pay increased attention to running in the engine of a new car for the first thousand kilometers, fulfilling all the recommendations. In what mode in the future to operate the vehicle, everyone decides independently.

In the design of the car, in addition to the engine, there are also systems that need lapping and running-in.

  • Chassis . Its components – racks, hubs, wheels, springs, bearings in the hubs, stabilizers, suspension arms and ball bearings – also during the movement are rubbed against each other, that is, they need running-in. All these parts must be inspected periodically before and during the break-in process, as well as during subsequent operation.
  • Steering . Components of the system: steering wheel, steering column mechanism, tie rods, steering rack with power steering, steering tips and rotary levers. These nodes are run-in, but do not need frequent inspection. Their condition should be monitored after a considerable time and replaced as they wear out.
  • Transmission . The gearbox consists of the following nodes: connecting link, clutch (sometimes hydro and cable). When a new car is run in, the clutch disc is lapped on both sides of the drive and follower discs. The constant velocity joint is subject to wear over a long period of use.
  • Anti-lock braking system . It consists of the following units: working cylinders, brake drums, brake discs and parking brake drive. During break-in, the brake discs are lapped. Other systems do not need to be run-in. You will need to change them as they wear after a significant period of operation.

Automobile production around the world is constantly being improved, and this applies not only to the most prestigious brands, but also to cheap models. This is facilitated by the development of technology in the engineering industry. Computerization of processes at all levels, the use of a laser to process parts, the introduction of modern materials allows us to make production more accurate and get the perfect end product. At the same time, requirements for the quality of fuel and oil are also increasing. But none of the improvements yet allows you to abandon the break-in.

Any man dreams of a beautiful new car, and of course, that after the purchase, he takes good care of his iron horse. Moreover, for such an acquisition, you have to lay out a considerable amount. Of course, every car owner is interested in extending the life of the car. Running-in allows to avoid breakdown of the most expensive part of the car – its engine, to maximize the operational life. In this case, caution will not be superfluous, as any experienced driver or auto mechanic will tell you with confidence.

Dmitry Petrov

Dmitry Petrov is an engineer who specializes in materials science, and has a deep passion for all things related to automotive technology. He is a true motorhead at heart, and spends much of his free time tinkering with engines and studying vehicular dynamics.


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