Contents: What is attractive about diesel? ⤓ Why is diesel noisy? ⤓ Diesel Care ⤓ Buying a used diesel ⤓ Be healthy diesel ⤓
If you are thinking about switching to diesel but do not know how to take care of it yourself, then we will immediately say that maintaining a diesel engine in good condition is no more difficult than a gasoline engine.
Diesel cars are renowned for their durability, but that doesn't mean they don't need to be looked after.
Prices for used diesel cars in the West are falling. This is due to the fact that for a long time the sales volume of new diesel cars was very high and therefore there are a lot of them on the used car market now. New diesel cars are much more expensive than their equivalent petrol counterparts. In addition, the time has passed when the diesel range we are accustomed to today was limited to just one model. Today, manufacturers are able to supply the market with diesel engines that meet the highest requirements
It is a pity that countries, if there are any, where diesel fuel costs the same as gasoline or even more. But even in this case, you will be in the winner"s seat, since diesel cars usually have a longer service life, but only if you have a high annual mileage. No savings are achieved only with low annual mileage. You save on spark plugs, although it is clear that when using spark plugs with a replacement frequency of 60 thousand km, the savings on them will be small. At the same time, you will lose on more frequent oil and filter changes.
What is attractive about diesel?
Modern diesel cars are attractive because of their ability to develop high traction force at low revs, which is especially good for drivers who do not like to change gears too often. Most manufacturers offer turbocharged diesels to give the owner the opportunity to experience the full charm of a high-class car.
If you are thinking about switching to diesel, but do not know how to take care of it yourself, we will immediately say that maintaining a diesel in good condition is no more difficult than a gasoline engine, despite their differences. We offer you a short guide to buying, operating and maintaining a diesel engine
The mechanisms of a petrol and diesel engine are not much different. Both engines operate on a four-stroke fuel combustion cycle, but they do this in completely different ways
While gasoline engines ignite the air-fuel mixture with spark plugs, diesel fuel is ignited by very high compression.
When a gasoline engine sucks in air and gasoline on the first stroke, a diesel engine sucks in only air, which is compressed to such an extent that its temperature rises to 800°C. The hot air ignites the diesel fuel, which is injected into the combustion chamber of the cylinder shortly before the piston reaches TDC on the compression stroke. Since the compression ratio of diesel engines is twice as high as that of gasoline engines, the fuel must be injected under very high pressure so that it flies into the combustion chamber and the fuel stream retains the shape given to it. Due to the increased requirements for injection, the high-pressure fuel pump of a diesel engine is a particularly high-precision-manufactured unit.
On older diesel models, high-pressure inline multi-plunger fuel pumps were usually used. Now most modern diesel engines use more sophisticated rotary pumps with a constant fuel supply, as they work better at high engine speeds. Modern diesel engines use electronic fuel metering control systems to achieve a combustion process that is close to ideal. Many diesels are even equipped with neutralizers for cleaning exhaust gases.
There are two types of diesel engines and the difference between them is how they burn fuel. Some use direct fuel injection. The name itself indicates the direct direction of fuel into the combustion chamber cavity. Although this injection method is very effective, its downsides are loud noise and unevenness. For this reason, direct injection has been preserved only in diesel engines used in trucks. However, in diesel engines of improved design, these disadvantages have been largely eliminated and most car manufacturers offer highly efficient diesel engines with direct injection.
In other diesel engines that do not use direct fuel injection, a small additional chamber is created in front of the combustion chamber, into which the fuel is injected. This chamber is located on the opposite side from the injector installation location and the direction of movement of the fuel injected by it. This design technique allows increasing engine speed, but this comes at the cost of some loss of power.
Why is diesel noisy?
The familiar roar of a diesel engine is caused by the combustion of fuel and the subsequent sharp drop in high pressure in the combustion chamber. The specific roar of a diesel engine is most clearly heard after starting during the warm-up of the engine at idle speed.
The diesel engine does not have an ignition system, but it does have a system for pre-heating the combustion chambers of the cylinders using spark plugs. In addition, the times of prolonged cranking of the engine with the starter and tedious waiting for the indicator lamp of the end of pre-heating to go out are long gone. Many manufacturers are already producing quick-start diesel engines, which take no more than a couple of seconds to start in winter. Some cars even have a "starter handle" that can directly control the high-pressure fuel pump to change the injection moment, speed up warming up and reduce smoke emissions during start-up.
Diesel Care
Because diesel engines contaminate the oil in the lubrication system faster than gasoline engines, most vehicle manufacturers require more frequent oil and filter changes.
Special diesel oils are widely available today and, according to reviews, are quite effective. However, any high-quality motor oil for carburetor engines will also work for diesels, as long as it is changed at certain intervals. Read the label on the can, which is usually where the manufacturer gives instructions for diesels. If you do not find anything on this label, then look at the label on the container in which the cans were packed.
For engines with an overhead camshaft, the timing belt should be replaced at the specified intervals. Otherwise, the piston may collide with the valves when the belt suddenly breaks. Eliminating the consequences of the latter will require considerable financial costs from you. In practice, there have already been cases of belt breakage with a mileage of up to 48 thousand km, but this happened as a result of oil or water getting on them due to depressurization of the lubrication and cooling systems, respectively. However, if you decide to drive without changing the belt after a mileage of 58 thousand km, then your unwillingness to spend time on a timely belt replacement may result in significantly greater time and money costs for you in the future.
To replace the fuel filter, buy the best one available to you. Some filters may look good on the outside, but "do their job poorly." Don't forget to also replace the sealing ring on the filter housing. It is also important to note that on a diesel engine, it is equally difficult to prevent both fuel leaks and air leaks into the fuel system, which greatly disrupt engine operation.
If air gets into the fuel lines, it may be necessary to remove it from there through a special valve using a small hand pump, usually mounted for this purpose on the high-pressure fuel pump. Many modern diesels have fuel systems that automatically remove air. You just need to turn the engine with the starter, and the air will be removed.
It is difficult to avoid moisture condensation in the fuel filter, so some diesel engines are equipped with a warning light on the instrument panel to indicate the presence of water in the fuel system.
Usually, when changing the oil, you only need to check the filter condition. However, if the car is used in difficult conditions, such as high humidity and large differences between day and night temperatures, you should check the condition of the filters more often.
All diesels smoke when cold, but this should not be excessive. One of the most common causes of this is a failure in the fuel injection timing of the high-pressure pump, which is easily eliminated by re-adjusting the injection timing using the marks on the crankshaft and pump. This work is very similar to adjusting the initial ignition timing on a gasoline engine. The operation can be done with the engine off, but it is better to purchase a special lamp for setting the injection timing on diesels for this purpose, which is attached with a clamp to the fuel supply pipe of the injector and flashes under the action of the impact of the fuel passing through the pipe.
Another reason is fuel leakage through injectors with a loosely closed fuel supply channel, which can lead to overfilling of the cylinder with fuel and, as a result, to excessive smoking during start-up. Apart from general cleaning of the injectors and replacement of worn ones at a mileage of about 110 thousand km, there is little that can be done at home to check their operation. Unless you remove them and have them checked on some kind of control equipment.
New injectors are not cheap, but you can save a considerable amount by going to a diesel repair station and calibrating the injectors at a very reasonable price. The price of the service depends on the location of the station and the availability of spare parts stores around it.
However, you can extend the life of your injectors by keeping the air sucked into your diesel engine and the fuel filters clean, thereby preventing injector contamination. To do this, periodically add a small amount of special cleaner to the fuel tank.
If you take care of the high-pressure fuel pump, it will function properly for a long time. However, we would like to warn you that replacing it is quite an expensive undertaking.
Poor starting and low throttle response of a diesel engine can be caused by many things: poor quality spark plugs, clogged fuel line channels leading to a drop in fuel supply pressure, faulty fuel lines and even incorrect installation of injectors. It is easy to determine poorly functioning spark plugs by how long the pre-heating indicator light does not go out.
The following table of possible diesel engine defects has been compiled by Bosch and we hope that it will help you get your engine back into working order.
Talk to diesel owners and you will find that none of them would even consider driving a petrol car again. Maybe it is your turn if diesel suits your needs.
Buying a used diesel
Be careful when buying a used diesel. Diesels last a long time, but that doesn't mean you shouldn't inspect all the traditional wear areas. On some engines, it's very easy to disguise both the age and wear. There's a risk of getting screwed when assessing the condition of such an engine if you don't know much about diesels.
Like petrol engines, diesel exhaust should be homeless. Also, there should be no smoke coming out of the open neck of the oil filler tube on a warm engine. Since diesel engines are noisier than petrol engines, you should distinguish between operating noise and the knocking of worn pistons, connecting rods, camshafts, etc. If you have any doubts about the condition of the engine, seek professional help.
Turbodiesels are very popular because turbocharging fits well with diesel engine characteristics. Turbochargers operate at low boost pressure and low engine speeds, which gives them a longer service life than gasoline engines. Turbodiesels are excellent for tractors and multi-ton trucks.
However, diesel automatics have a hard time meeting the demands of an automatic transmission due to the flat torque curve. Only a few manufacturers are concerned about this problem. Among them are Citroen, Mercedes, Peugeot and the recently joined Opel, but even then they only use automatic transmissions in mid-size cars.
Thanks to their ever-increasing popularity, diesels are no longer looked upon as the poor cousin, and are now fully on par with their petrol counterparts in terms of trim level.
When buying, pay attention to the residual value of the diesel. Diesel cars once gave impetus to the growth of car sales in Germany, but sales peaked four years ago and have been gradually declining ever since, so make sure you are not overpaying for the privilege of owning a diesel car.
Check the mileage. Diesel cars are bought for their potential for high reliability and possibly high mileage, especially when they are bought new. But this does not mean that you should not pay attention to the odometer. Indeed, many dealers do not like to deal with cars whose mileage has exceeded 80 thousand km and, accordingly, adjust the price for them. Or, without further ado, simply reset the mileage on the odometer. A mileage of 160 thousand km is quite normal for a well-maintained diesel, but think twice if the meter shows 320 thousand km or, especially, if it is a used taxi with such a mileage.
With the exception of the engine, most diesel cars are identical in design to their petrol counterparts, the same applies to suspensions, brakes, but consider the prices of spare parts. For example, exhaust systems last a long time, but differ from similar petrol engines. And if you are used to buying spare parts from car dismantlers, then keep in mind that petrol engine parts may be similar in appearance and fit in size, but the diesel cylinder block differs from a similar block of a petrol engine and in most cases cannot be selected as a replacement. Gear ratios of gearboxes and clutches also differ.
Be healthy diesel
The engine sneezed once, twice and died down... Anyone who has ever found themselves in such a situation probably knows what a swarm of questions runs through their heads during unsuccessful attempts to restart the "heart" of the "iron horse". Owners of cars with diesel engines are no different from everyone else, but the causes of problems with diesel engines and ways to eliminate them are largely specific to this type of engine. In order not to complicate your life, it is better to listen to the advice of professionals who have solid experience in this area.
They were contacted this time as well, and received a lot of useful information and fairly easy-to-implement practical advice.
The biggest surprise is that the engine, which was trouble-free yesterday, suddenly refuses to "come to life" at the very moment when you are rushing to work in the morning. If this happens for the first time, and is accompanied by white exhaust, then you can say with almost complete certainty that the glow plugs are to blame. By the way, the indicator on the instrument panel may well be wrong, claiming that everything is OK with the plugs. To check, one end of the wire is connected to the "plus" of the battery, and the other supplies voltage directly to the plugs. If a good spark jumps (it is easy to distinguish from a bright flash of a short circuit), the wire begins to heat up, and after that the engine starts, then the plugs are not to blame. The malfunction should be looked for in the electrical circuits that supply voltage to them. In this way, you can also check the fuel supply valve.
And finally, blame only yourself if you tried to start the car on the move before. The timing belt could easily slip through several teeth. The engine will not start and you may need to prepare for a complicated and expensive engine repair.
Experience shows that another situation is also very common - the engine is idling, and when you try to increase the speed, it immediately stalls or stops after working for a little while. Most likely, air has entered the fuel system. Again, it is worth paying attention to the exhaust. In this case, it is usually white with a characteristic smell of diesel fuel. A vacuum in the fuel flow can occur due to a blockage, say, of the fuel intake or fuel filter. Most often, it is the fuel filter that gets clogged, and such troubles occur mostly in winter.
Technodiesel specialists advise everyone to follow a rule that has no exceptions: never repair fuel filters. Various "flushings", "blowings", and other supposedly restorative procedures will, at best, simply have no effect, and at worst, will make the situation worse. Fuel, passing through such a "restored" filter, not only does not receive the required cleaning, but also washes away all the dirt that has previously accumulated in the filter. This can quickly disable the precision mechanism of the high-pressure fuel pump.
Another pseudo-help for the engine that "knowledgeable" mechanics like to provide is the installation of several fuel filters. From the point of view of achieving unprecedented purity of the diesel fuel entering the engine, there is no point in this multi-stage filtration. Manufacturers of diesel cars carry out precise calculations of the filter performance, which are confirmed by entire series of tests, so they are worth trusting. Additional filters are not just useless, but harmful. They create excessive resistance, due to which the high-pressure fuel pump works with an overload and fails faster. Increased resistance in the pipeline can also cause air suction.
You should not follow another fairly common misconception that additional filters help separate water from fuel. In fact, filters do not retain water; there are special separators for this purpose. The presence of such a separator is indicated by a small plug under the filter. The accumulated moisture should be drained approximately every 3,000 km. The liquid should be drained until almost clean diesel fuel flows.
Water in the fuel also causes white clouds of exhaust gases. Some modern diesel cars have an indicator on the dashboard that will tell you that there is water in the fuel. If the indicator lights up, it is better to stop immediately, turn off the engine and drain the liquid from the separator. If necessary, you can repeat the procedure. If the indicator does not go out after this, then the problem is probably in the electrical circuits of the water-in-fuel indicator system. You should not try to fix something quickly, it is better to contact a car service.
It also happens that a steadily humming engine suddenly goes silent for no apparent reason. The most trivial piece of advice, which, oddly enough, helps in many "difficult" cases - make sure that there is still diesel fuel in the tank. If the situation is worse, and something really happened, it is worth remembering; was there any sharp sound before the engine stopped. This sound is accompanied by a timing belt break. If so, it is better not to try to turn the engine - the consequences can be disastrous.
Another reason for the sudden engine stop may be the same air in the fuel system. You can try to directly connect the fuel pump to any container with diesel fuel. If the engine starts working, then the cause has been found. For any problems with the fuel pump, it is best to contact specialists, not trusting the repair to dubious mechanics.
When the high-pressure fuel pump is excluded from the probable culprits of the troubles, you can try to loosen the nipples on the injectors. If during attempts to start the engine, diesel fuel starts to flow out from under them in a pulsating stream, this means that faulty injectors do not provide a normal supply of fuel to the combustion chambers. Perhaps you will notice that black smoke has poured out of the exhaust - this is one of the signs of a stuck needle in the injector. Fuel begins to flow uncontrollably into the cylinder, and the black exhaust is due to its incomplete combustion.
Attention! And one more thing - do not recklessly drive through deep puddles. Masters often have to see diesel engines damaged after such a bath. Water from the puddle gets into the combustion chamber, and the strongest hydrodynamic impact bends even the strongest connecting rods!
Table of faults and methods of their elimination on diesel with fuel equipment of Bosch
| Malfunction | Possible cause codes |
| Difficult start | 1-9,12,13,20,22 |
| Erratic idle | 1,2,14,18,21,22 |
| Uneven idle speed of a warm engine | 2,10,'13,17,20,22 |
| Engine misfires under load | 1,2,4,5-10,16,22 |
| Engine power loss | 1,4-7,9,10,11, 13,15,16 19-22 |
| Increased fuel consumption | 7,9,10,11,13,14, 19,21,22 |
| The engine does not stop | 3,21,22 |
| Poor throttle response, black smoke from exhaust, loss of engine power | 2,5,9,10,11,13, 19-22 |
| Blue exhaust at maximum load (white or blue) | 1,2,4,5,8,9,13, 19,22 |
| Abnormal minimum and maximum idle speed | 14,15,18,21 |
| The engine does not accelerate | 1,2,4,6,8 9,10, 19, 20, 21 |
| High pressure fuel pump overheating | 16 |
| Possible malfunction | Methods of elimination |
| 1 Empty fuel tank or clogged fuel tank vent valve | Fill the tank, flush the fuel lines, clean the vent valve |
| 2 Presence of air in the fuel system | Bleed the fuel system, eliminate air leaks |
| 3 The diesel electromagnetic valve or the starting fuel supply regulator is faulty | Repair or replace |
| 4 The fuel filter is clogged | Replace the fuel filter |
| 5 Low pressure fuel lines are clogged | Restore the flow cross-sections of fuel lines |
| 6 Low pressure fuel lines are clogged | Flush or replace fuel lines |
| 7 Loose connections, leaking or broken fuel lines | Tighten the connections, eliminate the leak |
| 8 Paraffin deposits in the fuel filter | Replace filter, use seasonal fuel |
| 9 Incorrect fuel injection advance | Adjust the initial fuel injection advance angle |
| 10 Injector nozzles are faulty | Repair or replace |
| 11 The air filter is clogged | Replace the filter element |
| 12 Pre-heating system is faulty | Replace faulty spark plugs |
| 13 The injection distribution among the cylinders does not correspond to their firing order | Re-arrange the high pressure fuel lines in the required order |
| 14 Abnormal idle speed | Adjust the idle speed with the screw |
| 15 Abnormal maximum idle speed | Adjust the maximum engine speed with the screw |
| 16 The bypass valve is clogged or faulty | Clean the calibrated channel or replace the valve |
| 17 The discharge valve (on a four-cylinder diesel engine) or two valves (on a six-cylinder engine) are leaking | Replace valve(s) |
| 18 The force of the buffer spring of the diesel engine speed regulator is not adjusted | Adjust the buffer spring force |
| 19 Fuel injection advance clutch is faulty | Repair or replace the coupling |
| 20 Low compression | Restore compression |
| 21 Engine speed controller is faulty or not adjusted | Adjust or replace the regulator |
| 22 High pressure fuel pump is faulty or cannot be adjusted | Remove the pump and send it for repair |