How to determine the condition of the engine when buying a car

Ways to check the engine when buying a used car

Buying a used car is a fairly responsible procedure, as it involves a large number of legal and technical checks. As for technology, that is, analysis of the condition of the vehicle itself, when buying a used car, maximum attention should be paid to the most expensive elements: the body, engine, transmission, individual components of the chassis and steering.

If the condition of the body can be assessed visually, and the serviceability of the chassis can be easily checked on a lift and tested on the road, then the issue with the engine is not so easy to resolve. As a rule, the seller will not allow you to open the engine for diagnostics. Similar difficulties arise when it is necessary to check a removed engine when purchasing a contract power unit.

In this article, we intend to talk about how to check the condition of the engine when buying a gasoline car, as well as what methods help to check a diesel engine when buying a car.

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Checking a used engine before purchasing

Let's start with the fact that a lot about the condition of the engine can be learned by visually inspecting the engine itself and the engine compartment. First of all, you should remember that an apparently clean engine that starts and runs does not mean that the engine is fully functional and in good condition.

Experienced mechanics at service stations are well aware of this, and car resellers and less than honest sellers are also well aware of this. For this reason, when assessing the condition of a used internal combustion engine, you need to clearly know what to look for.

Before you begin your engine inspection, start with simple questions regarding vehicle and engine repairs and maintenance. Ask what was done on the engine and when, at what mileage the engine oil was last changed, when the belts and rollers or timing chain, antifreeze, spark plugs, etc. were replaced.
Also inquire about the type and brand of oil used (for example, synthetic, semi-synthetic, 5W30 or 10W40) and other technical fluids. At the same time, observe the clarity and transparency of the answers and the owner’s reaction.

This approach will immediately allow you to identify either a reseller who does not know the history of the car, or a careless owner who did not pay proper and timely attention to the car.

Visual inspection of the motor

Next, you can proceed to inspecting the engine. If the seller prohibits or deliberately makes it difficult to access certain external elements under the hood, then it is better to immediately refuse to purchase such a car. If no problems arise, you can continue.

As we already said, the first thing you need to pay attention to is traces of engine oil. Oil drips or traces of antifreeze will indicate leaks through gaskets, seals and other seals. In some cases, such problems can then be corrected without major financial investment, while in others, oil can be squeezed out as a result of serious engine failures.

It turns out that a worn gasket or oil seal may be leaking, which is not so difficult to change. However, in some cases, similar leaks can occur for other reasons. For example, when the engine was overheated, the cylinder head may then “lead”, that is, the geometry of the mating plane is disrupted. As a result, replacing the gasket will no longer solve the problem.

The other side of the coin is a recently washed, completely clean engine. As a rule, washing the engine compartment is done in two cases:

in order to give the car a general presentation;
to hide oil and technical fluids;

Unfortunately, the second case is much more common, since a working engine is rarely washed before sale. Moreover, the sellers specifically draw the buyer’s attention to the fact that the engine is dusty and the engine was not specially washed, that is, it is clearly visible that there are no leaks.

Either way, the discovery of leaks is a cause for concern and/or bargaining. A clean motor should also be cause for concern, which will require a more thorough check. The best option is an engine that is covered with a small layer of old dust, but does not have any leaks.

Checking the condition of oil and antifreeze

If you don’t know how to check a diesel engine when purchasing or you are interested in checking a gasoline unit, then you should start by assessing the condition of the technical working fluids inside the internal combustion engine. We are talking about engine oil and coolant of the cooling system.

Let's start with the oil. The first step is to unscrew the oil filler cap. Ideally, the lid itself should have no traces of obvious oiling on the outside, and the inside surface should also not be dirty, with traces of oil foam, etc. The last statement is also true in relation to the walls of the neck.
Next, you can take out the oil dipstick and assess the condition of the oil. If it is fresh, transparent, and free of foreign impurities and foam, then it will be difficult to quickly determine anything. Black oil indicates that either the lubricant has not been changed for a long time, or the oil quickly turns black as a result of general contamination of the internal combustion engine and the presence of problems.

What should be especially alarming is that the oil in the engine may foam, that is, an emulsion will form on the oil filler cap and/or on the dipstick. In this case, it becomes obvious that liquid from the cooling system is entering the lubrication system. Note that in such a case, either immediately negotiate with the seller the cost of a similar contract motor/overhaul, or stop further inspection.

In some cases, the culprit may be a broken cylinder head gasket, while in others the possibility of hidden cracks in the cylinder head or cylinder head cannot be ruled out.

Diagnostics of engine condition using spark plugs

Checking spark plugs can identify a number of potential engine and system problems.

Attention should be paid to such things as:

oiling;
black, red or white soot;
traces of unburnt fuel;

The above and other signs are a clear indicator of certain problems. It is worth considering, since checking the engine by the color of soot and the condition of the spark plugs is an effective method only if certain conditions are met, we recommend reading about such diagnostics and nuances in our separate article.

Extraneous sounds and engine vibration

Assessing engine performance at the initial stage involves identifying extraneous sounds, tripping, misfires and mixture ignition, as well as other failures in the operation of the internal combustion engine.

After the engine has been started, you need to listen to its operation, and also look at the level of shaking and vibration. If possible, you can use a stethoscope, which will allow you to listen to hidden defects and localize suspicious noises.

Both various systems (ignition, power supply) and individual components inside the internal combustion engine can fail. The crankshaft, pistons, hydraulic compensators or valves, connecting rods, etc. may be knocking. Shaking and vibrations can be a consequence and a sign of breakdowns, but the possibility of problems with the engine mounts should also not be ruled out.

To study the problem of knocking and extraneous noise in more detail, we recommend reading our separate article on the topic of knocking in the engine. As for vibrations, we also offer you extensive material for your reference.

Analysis of the color of exhaust gases when checking the engine

The color and intensity of the exhaust, as well as the composition of the exhaust gases, in many cases clearly indicate the presence or absence of problems with the engine and its systems.

Let's start with the fact that on a properly warmed injection engine in the warm season, practically no smoke is visible. There is also no exhaust smell. In the case of a carburetor, you can sometimes observe light grayish-white smoke, the smell is clearly present.

Oily blue smoke is a sign of oil consumption, wear of the piston rings and CPG. Black smoke indicates severe coking, problems with mixture formation and combustion of the fuel-air mixture.

Checking the engine while driving

So, if the engine runs smoothly, does not smoke, does not knock or vibrate at idle, and also responds quickly and clearly to pressing the gas pedal, then you can take a test drive.

Let’s make a reservation right away: a short drive will not be enough. It is important to evaluate the operation of the unit in different modes, as well as warm up the engine to operating temperatures. For this reason, you should count on a distance of at least 10-15 km.

To solve the problem, you should offer the car seller reasonable compensation for spent fuel and time costs. Next, you need to ask the owner, who will be in the car with you, not to make noise. You will also need to turn off the speaker system to be able to listen to all extraneous sounds.

First of all, take a look at the dashboard to see if the check engine light comes on periodically. At the same time, evaluate the sound of the engine when accelerating, during engine braking, during sharp acceleration, etc. Also, while driving, you can listen to the engine alternately with the driver and/or passenger window open and closed.

Check the oil level and condition again, also allow the unit to cool a little and look into the expansion tank, assess the condition and type of coolant. There should be no smoke coming out of the tank, and there should be no oil stains on the surface of the antifreeze.
If the situation allows, you can re-unscrew the spark plugs and re-evaluate their condition. In some cases, it is possible to reach an agreement with the owner and even measure the compression (if the buyer has a compression meter).

Useful tips

As you can see, a superficial inspection and check of the engine before purchase allows you to identify a large number of hidden defects with the right approach. If you are not confident in your abilities, then the right decision would be to order a comprehensive diagnosis of the power unit and the entire vehicle at a service station. Specialists will conduct computer diagnostics, point out possible problems and immediately announce the approximate cost of repairs.

In the future, the information received can be used as a valid reason for refusing to purchase or reasoned bargaining. Finally, let’s add that for quick diagnostics of cars with an ECM, it is useful to have a compact diagnostic scanner-adapter for the OBD2 diagnostic connector. The device allows you to quickly scan the system for errors, as well as evaluate the operation of engine systems in real time.

How to check the engine when buying a car

The engine is the main part in a car. This is the heart of the car, which, in fact, makes it go. The engine is expensive. Even contract engines for budget cars can cost hundreds of thousands of rubles, which sometimes exceeds the cost of the used car itself.

The price of the engine is at least 70 percent of the cost of the car, so checking the car's engine is the main step before buying a used car. The check is performed in several ways, and you can find out not only about the condition of the engine, but also its number. With the help of technology it is easy to calculate even the real power of the unit.

There are a number of ways to check the engine of a car before purchasing, and today we will look at them in detail.

Content

Self check

A method for those who understand cars and can determine the condition of the engine themselves. If you decide to check the car engine yourself, then start by opening the hood of the car.

When checking yourself you need:

Inspect the engine itself for leaks, foreign liquids and deformation of the housing from impact. After this, the presence or absence of some common problems, such as damage from external impact (frontal impact) or oil leaks, will become obvious. If the engine under the hood of a used car is dusty and dirty, then you are in luck: a clean and washed engine does not show any leaks of oil or other liquids. You should inspect the engine for leaks during daylight hours and with a flashlight, in other words, with maximum illumination of the engine compartment. If the engine has recently been washed, then all that remains is to ask a question about oil leaks, counting on the seller’s honesty, otherwise such a defect will be identified over time after purchasing the car, and this will become an unpleasant surprise.

While you are near the running car, you can check the sound of the car's engine. It should operate smoothly, without changes in sound and without making the sound louder or quieter without pressing the pedals. It is worth remembering that the sound of a diesel engine is different from the sound of a gasoline engine - it “rumbles” like a tractor, while a gasoline engine operates in the same key. The sound of boxer engines, which are found on some sports cars, for example, on the entire Subaru line, is also different - these engines “growl” even at idle.
Take a ride in a car. In fact, the only way to see the engine “in action” is the ability to independently evaluate the power and response to the pedal, to understand whether everything is working as it should, and whether the car is losing power, whether there are any “dips” when driving, and so on.
Inspect the engine compartment and find out if the car has had a frontal impact. If you can see that the front end of the car has been recovering from a severe accident, it is worth considering that this may affect the performance of the engine in the future.
Connect the diagnostic wire - if you have such equipment, you can read the error logs of the on-board computer and find out for sure what problems the engine has. But be careful – sometimes unscrupulous sellers use technology to erase errors from the computer’s memory.

If you have a diagnostic wire and you are checking a foreign car that is not too old, then connect a laptop through it and read the errors recorded by the on-board computer. In modern cars, the computer reads errors and saves them in a log, which can always be viewed using the appropriate equipment, which is simple and inexpensive: you only need an OBD cable, a laptop and software for your car brand.

If you are unlucky and come across a “dead” car, the computer will generate a bunch of errors, including engine errors. Next, you simply compare the error numbers with the database and get information about what exactly is wrong, and there can be a huge variety of different defects: from malfunctioning engine mounts, leading to vibrations in the cabin, to missing ignition coils or scuffing in the cylinders.

Checking at a car service center

A surefire way to learn everything about a car and its engine if you don't consider yourself a good expert to inspect it yourself. For a reasonable fee, service specialists will inspect the car completely, consider it a computer (if the car has a diagnostic connector), check all the technical components of the car and even find out whether there has been interference in the memory of the on-board computer, whether the mileage has been changed through it and whether errors have been erased.

It is better to contact either official dealers or specialized centers that work with one brand of car, or with a narrow range of car brands. As a rule, such services know better all the typical “sores” of cars and are very well versed in the engines presented on the brand’s models.

In this case, you only need to choose a service that has a large number of positive reviews and a long history of work, pay for the service and wait until the diagnostics are completed, after which you will be given a work order. Whether you buy a car after that and pay for spare parts and repairs, or hand over the document to the seller and refuse to buy the car, is up to you. This method of checking a car engine is very effective and, as a rule, error-free - if the car is faulty or requires significant investment, specialists will report this based on the diagnostic results.

Advantages of using a car service:

You will know for sure all the ins and outs of the car and its components: they will tell you whether the car’s mileage was low, whether there were any accidents, what exactly needs to be replaced or repaired at a given time, etc.
They will issue an order on the spot and tell you where to purchase spare parts and consumables. If you purchase a car right on the spot, you can begin to work on fixing problems without going anywhere.

Disadvantages of working with a car dealership:

It is necessary to pay for the services of a specialized service; prices vary depending on the region and the qualifications of the servicemen. On average, for services specializing in foreign cars, one standard hour is estimated at 900 to 2000 rubles, diagnostics last an hour and a half, these costs are borne by the potential buyer.
You will have to spend time on the road to the service, diagnosing the car and then on the way home, you also need to agree on a time that is convenient for all parties: you, the seller and the car service center. Due to the complexity of the organization, the process can take weeks.
If you choose an inexpensive service “behind garages,” there is a risk that the diagnostics will not be carried out efficiently, which will result in additional expenses for you after purchasing the car.

If you have enough time and are willing to spend several thousand rubles to definitely avoid mistakes, then the service is your option. But be careful when choosing the service itself; saving here is not the best way; it is better to spend more money on the services of high-level specialists.

On-site vehicle diagnostics

The service has come into use recently, but has managed to spread widely and attract a huge number of specialists. Today, anyone can order a car inspection at home; it’s practically the same as a car service, only specialists come to you, and not you to them.

As a rule, the inspection is carried out by automobile experts who work either as mechanics in a car service center or as specialists in the sale of used cars. With a trained eye, they will determine the condition of the car, conduct diagnostics through the on-board computer and tell you exactly what this car has experienced in the past, and what you should be wary of in the future.

The advantage over the service is that you do not need to go anywhere, and the check will be carried out faster, however, the weakness of field specialists remains the lack of complex equipment present in car services, such as a lift. However, if you have a garage with a pit, this problem is leveled out.

Specialists will come to you with a set of necessary equipment and inspect the car. The work takes from 40 minutes to one hour.
As a rule, on-site diagnostic specialists have carried out a similar procedure many times already, and with a trained eye they can quickly and accurately determine what exactly is wrong with the car. The quality of diagnostics and the “verdict” of field experts are usually very accurate.
Experts in car selection also negotiate with the seller for you, and you can “bring down” the price of a car you are interested in in good condition. Despite the fact that the price for such services is high, it is usually less than the amount that car selectors manage to negotiate for, and as a result, everyone benefits.

Lack of some professional equipment present in the car service.
There is a risk of encountering amateurs who incorrectly assess the condition of the car.

How to check car engine power

If you buy a powerful car with a lot of “horses”, it is probably important for you to know whether the engine has lost its potential over the years.

For such a check, it is necessary to drive the car to a power stand, a special device on which the engine is subjected to maximum load and they find out how much horsepower and torque the unit actually has.

Over the years, cars lose their former properties, engines weaken and lose horsepower, and only with the help of a power stand can you find out how many of them are left, and only then decide whether it is worth buying a car that has lost its former strength over time.

It doesn’t matter whether you check the car yourself or take it to a service center, you can always find out the most basic things about the car’s engine thanks to the Autocode online service. The free report based on the results of the inspection will indicate the type of engine, its power and volume, so you can calculate the tax on this car in advance and estimate fuel consumption.

By ordering a full report for 349 rubles, you will find out the entire history of the car: actual mileage, presence of traffic police restrictions, customs history, history of fines, information about compulsory motor liability insurance and those. inspections and much more.

Before buying a car, with or without checking its technical condition, it is always better to have a report on it. With its help, you can avoid significant losses and not face deception from the car seller.

If after receiving the report you are unable to travel for inspection, use an on-site inspection. The technician will arrive on site and diagnose the car using special instruments. Just order an Autocode on-site inspection and be confident in your purchase.

How to check a car engine before buying? (Photo and video instructions)

Good afternoon. In today's post, I will tell you how to check a car engine before buying. By carefully reading our instructions and watching the video, you will be able to diagnose the engine, even if you have never done this and have a very general understanding of the car’s structure.

How to check a car engine before buying without special tools?

Here's a video instruction for those who don't want to read:

Let's agree on the shore - such a check is very general, and when buying an expensive car, it is advisable to use diagnostic devices, since not all faults can be diagnosed without devices.

Attention.
It is advisable if you inspect a “cold” car, this way you will learn much more about the condition of the engine.

Step-by-step instructions for checking an engine when purchasing without instruments.

We begin the inspection with the exhaust pipe. With a finger, or better yet, with a napkin, we wipe its inside and make sure that there is no soot (for gasoline engines, a diesel engine, especially an old one, will have soot).
If there is soot, this indicates that the engine is either burning oil or has incorrectly configured fuel equipment. The reason will be determined by the color of the smoke, but that will come later.

The next step is to ask the seller to open the hood and visually inspect the engine. It’s great if the engine compartment is clean and a little dusty. In this case, all places of oil leaks are easily visible.

If the engine is washed, this indicates either the seller’s excessive love for cleanliness or a desire to hide small oil leaks .

If you observe oil leaks, you need to understand where the leak is coming from and how much it will cost to fix it. A leaking valve cover gasket is one thing - the cost of repair is 300-500 rubles. And another thing is the camshaft oil seal leaking, in this case the repair will cost 5-10-15 thousand rubles. Because You will also have to change the timing belt.

The next step is to look under the oil filler neck.
If the season is cold, a light coating of emulsion is acceptable:

If you see a picture like this:

Probably, antifreeze gets into the oil, and this engine will not run for a long time.
At best, it has a broken cylinder head gasket, and at worst, there are cracks in the cooling jacket. Those. There is a high probability of getting a contract engine replacement or major overhaul. At the same stage, take out the oil dipstick and check the condition of the oil. It should be something like this:

If there is an emulsion on the dipstick instead of oil, you can safely refuse the purchase or ask for a discount on the cost of the contract engine and the work to replace it.

The next step, if the seller allows it, is to unscrew the spark plugs and look at their condition. If you see a picture like this:

Everything is fine with the engine.
If the spark plugs are covered in black soot, as is the exhaust pipe, this is a reason to refuse the purchase, since the engine is probably burning oil or has problems with the power system. In general, if you are allowed to remove the spark plugs, you can learn a lot about the condition of the engine from them, but we have a separate article about this, and there is no point in repeating ourselves.

The next step is if the pump is driven by an alternator belt, as on the classic VAZ A or ZMZ 402-406, we try to forcefully chat and feel the play. It is unlikely that with a tight belt you will succeed, but if you have enough health, this is a good reason for bargaining.

The next step is to start the engine and listen/watch.
There should be no extraneous noise, much less knocking, in its operation, and the emergency oil pressure lamp should go out within 2-3 seconds. After that, go and look at the exhaust.
If you observe bluish smoke, this indicates that the engine is suffering from oil leakage.
Diagnosing the cause of this oil burn is very simple - if the engine smokes when re-gassing, after idling for 3-5 minutes, you can be sure that the problem is in the valve stem seals and repairs are not expensive. If the blue smoke comes out constantly, like in this video:

This indicates a faulty piston ring.
And this is definitely a major overhaul or replacement of the engine with a contract one. It's expensive, maybe it's better not to buy it.

The next step is to open the oil filler neck with the engine running.
The plug should be attracted, if the plug jumps, or even worse, tries to fly away, this indicates that the engine is faulty and the breakthrough of quarry gases is significantly increased. With a high degree of probability, the engine has reduced compression and, at a minimum, the engine will need to replace the piston rings, which means a complete disassembly and, in fact, a major overhaul. Remember - a working engine will suck the oil filler plug tightly.

The next step is after starting the engine and making sure there is no smoke or breakthrough of quarry gases. Warm up the engine to operating temperature (ideally before turning on the electric fan of the cooling system).

At the same time, we look into the expansion tank - no bubbles should appear in it, and there should be no oil stains on the surface of the antifreeze.

Turn off the warm engine and start it again. At the same time, look at the oil pressure lamps and check the engine. The check engine light should go off immediately after turning the key, and the oil pressure light should go off immediately after starting.

If after all these checks you do not see any faults, you can say that the engine is in good condition. But it is advisable to add several diagnostic devices.

Additional check of the engine condition using diagnostic tools.

When you go to view a car, it is advisable to have a few diagnostic instruments:

Compressometer.
Metal rod.
ELM 327 or a specialized scanner for a specific vehicle.
Endoscope.

How to check compression and what does it give?

The compression will show the approximate condition of the cylinder-piston group.
Absolute values should be found in the operating manual for the specific vehicle. Scatter is important! The spread between cylinders should not exceed 10%. The verification procedure is as follows:

warm up the engine
turn out all the candles
We measure the compression in the cylinders one by one, cranking the engine with the starter, with the gas pedal fully pressed.

Here's a short video measuring compression:

A metal rod is needed to listen to the engine and attachments.

— the rod rests against the running engine and is pressed against the ear (but not pushed inside). It's done something like this:

Using such a rod you can listen to the condition of the generator bearings, pumps, and even knocks in the crankshaft!

Despite its availability (price about 200 rubles). This is a very useful diagnostic tool. With the help of the ego and the program in your smartphone, you can tell a lot about the condition of the car.

This scanner can read all engine errors, show the main parameters and can measure acceleration time.
Actually, its capabilities are largely determined by the program used.
It is important for you to look at the absence of permanent errors, the condition of the catalysts and the main parameters (temperature, idle speed, pressure in the intake manifold). We have a separate article on engine diagnostics using ELM 327 on our website, and there is no point in repeating it.

If you don’t yet have this wonderful scanner, you can order it without any extra charges on Aliexpress.

If you plan to drive the car you are purchasing for a long time, it makes sense to take an endoscope with you for diagnostics.
This pleasure costs from 4 to 30 dollars and, depending on the price, has different characteristics.
To check for scoring in the cylinders, it is best to use more expensive devices connected via WIFI to a computer, since the image on the screen is larger.
Here is a video with an example of engine diagnostics using a USB endoscope:

You can buy endoscopes here. Personally, I use this model for inspection.

Conclusion.

That's all for me today.
I hope that in this article I was able to fully answer the question of how to independently check a car engine before purchasing. If you have objections, comments, suggestions, or just want to share your thoughts, write comments.

How to check the engine before buying a car. #9

Part 9 of the large guide “ How to choose and check a used car before buying .” Links to other parts are at the bottom of the article.

Attention! At the bottom of the post is a video version of the article. Choose what is more convenient - reading or listening.

The video version has more illustrations. Pikabu has a limit on the number of pictures.

In a telephone conversation with the seller, agree that he will provide the car for inspection in a “cold” state. Many, even serious problems, especially in their infancy, are not obvious on a warm engine. A cold start, even in summer, can reveal a lot of interesting things, first of all, extraneous sounds, the nature of which can suggest the nature of the problems.

Visually inspect the engine and adjacent pipes for fluid leaks, oil contamination (oil fogging) in the area of the valve cover gasket, cylinder head gasket, pan and oil seals.

If the engine compartment was washed before sale, perhaps to hide traces of leaks of working fluids. In fact, if there is a slight oil fog in the area of the valve cover gasket, covered with an old layer of dust, this is not very critical. This becomes a problem when it turns into a constant leak.

Inspect the drive belt, and if possible, the timing belt. The inner layers of rubber should not be visible on the sides of the belt, there should be no signs of delamination, and the belt should not have cracks. Of course, the belt and rollers should not “whistle” or make other uncharacteristic sounds.

The drive belt must not be oiled. If the belt has significant wear around the edges, it is possible that the pulleys will also have to be replaced. If such signs are detected, then the drive belt requires replacement - this is another reason for bargaining with the seller.

It is worth understanding that without disassembling the engine it is impossible to accurately determine the condition, level of wear of engine parts and remaining service life. But based on a number of indirect signs, you can weed out options that probably should not be considered for purchase.

Inspect the engine valve cover bolts. If they show signs of dismantling, this is a reason to ask the seller about the reasons. If the engine of a new car has been repaired, this is a reason to refuse the purchase, since it is not known what caused the repair, how well the repair was performed and what parts were used.

Among the indirect signs of malfunctions, one can note the condition of the engine’s working fluids, primarily oil. Unscrew the oil filler cap, check for deposits on the cap itself and look inside the neck.

If a thick white coating (emulsion) is found on the cover and on the internal parts of the engine, it means that the oil is mixed with antifreeze, which enters the working cavities of the engine through a broken cylinder head gasket. What’s worse, the geometry of the cylinder head may be disrupted, causing it to not fit tightly to the cylinder block, or the engine cooling jacket may have a crack.

Check for the presence of emulsion and other deposits on the engine oil dipstick, at the same time checking the oil level in the engine. An insufficient level may indicate significant consumption. But the normal level should not mislead you; perhaps the seller prudently added oil to the level before showing the car.

Excessive pressure should not be emitted from the engine dipstick hole, or, simply put, smoke profusely. There should also be no excess pressure or smoke coming out from under the unscrewed oil filler cap when the engine is running.

A large volume of blow-by gases may indicate problems with the piston group. The video shows an advanced case when the piston has already burned out.

Remove some oil from the dipstick with your fingers and rub it, there should be no abrasive or fine metal dust in the oil, which would indicate increased wear of engine parts.

The oil should not have a pronounced burning smell, which indicates severe overheating of the oil and that it has deteriorated its lubricating properties, which means the engine is operated in critical conditions. Also, the oil may have a burnt smell due to problems with the piston.

The obvious smell of gasoline in the engine oil is also a negative symptom. In particular, this symptom may indicate a malfunction of the injectors. If a faulty injector does not close completely, then after stopping the engine, the residual pressure in the fuel rail squeezes gasoline through the injectors into the cylinders.

The quality of the oil deteriorates, which exposes the engine to increased wear, and fuel consumption also increases.

A lot of thick oil deposits on the oil filler cap itself and inside the engine are also a bad sign. Firstly, the oil thickens if it is overheated, and this in itself is not very good - if the engine overheats.

If the oil has thickened due to the fact that it has not been changed for too long, this indicates the quality of service of the car as a whole. Secondly, thickened oil settles on the walls of the engine, clogging the oil channels through which oil flows from the pump to all rubbing parts of the engine, narrowing these channels.

Accordingly, the channels narrowed due to thick oil deposits supply an insufficient amount of oil to the rubbing parts, which can lead to increased wear of these parts.

Through the oil filler neck, using a flashlight, inspect the surfaces of visible engine parts. If there are a lot of hard deposits on them, similar to a crust, this may indicate the use of low-quality motor oil and/or fuel.

This is also not good and over time can lead to coking of the piston rings, which will no longer perform their function, which can lead to loss of compression and significant oil consumption. It should be noted that a small amount of carbon deposits is acceptable on a high mileage engine.

Also, excessive carbon deposits on the valves can lead to their incomplete adherence to the seat, which will result in a decrease in compression and valve burnout. In especially neglected copies, there may be so much significant carbon deposits on the cylinder walls that the volume of the combustion chamber decreases, this leads to increased friction and reduced heat dissipation, which cannot in any way have a positive effect on the operation and service life of the engine.

This phenomenon is accompanied by increased engine detonation and a drop in power. But this can only be diagnosed by looking into the combustion chamber, for example, using an endoscope.

What needs to be checked in the engine before buying a car and how to do it?

When buying a car, everyone should take a serious approach to checking the car, in particular the engine during the inspection.

At this stage, it is necessary to identify all existing shortcomings of the car.

Buyers often inspect the external parts, but much more about the “iron horse” can be learned by opening the hood.

Why do you need a survey before purchasing a car?

The first thing you need to pay attention to is the engine. But why? It is the “heart” of the car that makes the vehicle move. Even a clean and working engine does not guarantee that it is in good and well-maintained condition.

How is the verification carried out?

Visual inspection

Unlike the interior or body, the condition of the engine cannot be determined by eye. But no one will allow you to open this part. Don’t be upset, because there are a number of secrets and tricks that will help you determine the condition of the motor with high accuracy (even for a beginner!).

It's quite simple, you just need to know what to look for. If you are not an expert on engines or do not understand the structure of a car, never tell the seller about it. It is better to remain silent and listen carefully to what the owner is saying. But if he tries to evade any question, this may be a sign that the engine may have flaws.

First you need to conduct a visual inspection of the motor. It should be clean; if you see oil marks and smudges, this may indicate an existing problem. Even a few drops can cause serious problems associated with oil leakage in the future.

The causes of oil leaks and marks are worn gaskets or a loose clamp on the hose. Even if the seller cleaned the engine before showing the car, traces could remain on the inside of the body. Also check the engine nuts and bolts for scratches; they may indicate that someone tried to open it, which means the owner has something to hide.

You can ask to remove the pipe that connects the intake manifold and the air filter. It is necessary to remove the pipe that connects the air filter to the intake manifold. If oil is found in the pipe, this indicates wear or severe contamination of the air filter.

Motor oil and antifreeze

To check the engine oil, use the dipstick provided for this purpose. The oil should be free of small chips and visible impurities, light in color, not viscous and emit strong strange odors. If bubbles are found, this is a sign of a leak, which is a serious problem. If the oil begins to foam, water gets into it.

Check the antifreeze by unscrewing the radiator or tank cap. The presence of air in it means that it is leaking into the engine. There may be two reasons for this: a leaky gasket or a cracked cylinder head. It is worth remembering that antifreeze is a caustic liquid that can harm piston rings.

Ask when the engine oil, belts, and timing chain were changed. Find out the brand of oil. At the same time, ensure that the owner's responses are clear, prompt, and transparent. This will help you determine whether you are facing a conscientious owner or a careless driver, or even a second-hand buyer who does not know the car’s history.

Oil filler cap

Unscrew the neck cap and inspect it carefully. There should be no foam or plaque on it. Foam is evidence of water ingress, and deposits indicate that antifreeze is leaking into the engine.

Candles and rubber elements

There should be no oil on the spark plugs, but if there is, the piston rings will need to be replaced soon. Carbon deposits indicate a dirty air filter that needs to be replaced. If there are cracks, the engine will run with a knock. The surface of rubber elements must be completely intact, without the slightest damage or cracks.

How does it work?

After a visual inspection, you should check how the engine behaves during operation. The engine should start the first time; if this does not happen, this is a direct sign of a defect. Starts must be made several times at intervals, and you do not need to gas, but listen to the engine.

A slight tapping sound is acceptable when the engine is running, but there should be no other sounds under any circumstances. Rockers should not make noise and valves should not knock. If the described problems are present, this indicates a problem with the engine mounts, as well as malfunctions in the internal combustion engine components.

Next, drive in place, increasing the speed to 3000-4000 per minute, while avoiding jerking and vibration. If you try to accelerate sharply at idle and vibration is noticeable, then in these modes the car will lose power. When the engine is running, the instrument needles should be within normal limits, or better yet, at average values.

What kind of smoke is coming from the exhaust?

The exhaust intensity and color indicate the presence or absence of engine problems. If the engine is working properly in the warm season, there should be no smoke. But upon startup, abundant white smoke may appear, which quickly disappears - perhaps this is condensation. Nothing wrong with that. But if such smoke does not go away, but continues to come out of the exhaust pipe, and the color is bluish, the aroma is sweetish, then all this indicates the presence of antifreeze in the internal combustion engine.

Repeated diagnostics after a test drive

It is necessary to check the operation of the engine after a test drive, during which you can better hear the engine and “feel” it. And also watch how the car develops speed. After the test drive has been completed, inspect the engine; oil leaks are not allowed. If during a test drive the car drove jerkily and oil spilled onto the engine, refuse to buy it. The funds spent will not meet the expectations of the purchase.

Diesel engine inspection technique

Checking a diesel engine is almost the same as a regular one, but there are some nuances. Let's take a closer look.

It is necessary to unscrew the oil hole cap, but do not remove it completely. Ask someone to press the accelerator pedal, and watch for yourself: if the diesel engine retracts the lid, good; if it pushes out, this is evidence of low compression.
There should not be any traces of oil on the cover, but if they are noticed, this indicates overheating of the diesel engine.
Ask to press the accelerator pedal again, and evaluate the exhaust from the pipe yourself; if the color of the smoke is blackish, then do not be alarmed. But if the exhaust has a bluish tint, this is an indication that the turbine needs to be replaced.
Next, check the hole with an oil dipstick; smoke and steam should not appear.
Allow the engine to warm up to operating temperature before turning it off. Then it should start instantly.

What can you find out from the data on the mechanism?

It is necessary that this number matches the one on the body. This set of numbers can tell you about past sales and accidents involving this car.

Obtaining information about theft by VIN code

You can check your car for theft for free using the VIN code on the official website of the traffic police:

Go to traffic police.rf.
Move your mouse cursor to the right over the “Services” button and go to the “Vehicle Check” service.
Enter the VIN in the line that opens and scroll down the page to the subsection “Checking whether you are wanted.”
Click on the “Request Review” line.
Enter the code from the picture and wait for the verification result.

Having considered the tricks and secrets of checking a car engine when purchasing, you can be sure that this procedure does not contain anything complicated. It is only important to remember the basic rules. Then everyone will be able to choose a decent car.