Contents: Initial examination ⇊ Before starting the engine ⇊ "Cold" start ⇊ Warming up the engine ⇊ A beautiful, sonorous voice means a…⇊ A healthy mind resides in a healthy…⇊ Exhaust smoke analysis ⇊
Is everything OK with the car engine? Maybe it's time to put money aside for computer diagnostics, or even repairs? A few tips from an auto engineer who has been repairing imported cars for many years will help you answer these questions.
Before going to the doctor, each of us does self-diagnosis. At the same time, we do not perform X-rays on ourselves, do not use an electrocardiograph or other sophisticated devices. We simply feel the forehead, examine the throat, listen to see if there is a sizzling sensation in the chest, if the stomach is bloated, if the lower back is contorted. Of the devices, we traditionally use thermometers and, perhaps, wristwatches when measuring pulse.
This is how, in simple terms, we determine whether the body is functioning normally. And it works!
A car engine is the same organism. There are many clever devices, tools and instruments for its accurate diagnosis and treatment. Various precise methods and techniques are used, requiring a subtle knowledge of the internal structure. we plan to tell you about them in detail in the near future.
To begin with, we suggest mastering things that are easier to understand.
Let's try to figure out what you should pay attention to when operating a car: what you need to touch, where to look, where to listen and maybe even smell to understand how the engine feels. If you don't want to study with us, take a hundred dollars out of your wallet and go for a computer diagnostic. Automobile "medical care" is paid!
Initial examination
Imagine that you are a good doctor. Upon entering the room (garage), approach the patient (car), be sure to say hello, say a few kind, calming words to him and offer to undress to the waist (open the hood).
Start with an external inspection of the engine. Remember that nothing reflects inner well-being like a pleasant, well-groomed, healthy appearance.
Severe general contamination of the engine, as well as the presence of intense local leaks, on the contrary, indicate poor health. If you prudently placed a clean sheet of newspaper under the engine when leaving your car in the evening, take it out and inspect it. Oil and other operating fluid leaks will leave marks on the newspaper overnight, which will allow you to identify the source of the leaks and determine their intensity. The higher it is, the sooner you need to take action to eliminate the problem.
The next step is to check and bring the level of all operating fluids to normal. First of all, we are interested in engine oil and coolant (antifreeze), since their deficiency has the greatest impact on the technical characteristics of the engine.
I would also like to remind you - believe me, I am not joking - that you need to make sure there is fuel in the tank. Experience shows that some inattentive drivers almost torture the starter and battery to death, forgetting that first the young man needs to be fed and watered, and only then - on the shovel and in the oven.
At the same time, check the tension of the drive belts of the engine's auxiliary units (cooling system pump, generator, power steering pump, air conditioning). Make sure the belts are not sagging or torn. If everything is okay, dust off your trousers and get behind the wheel.
Before starting the engine
Don't rush to start the engine right away. There is no need to rush here! First, turn the key to the "ignition" position... As a rule, a number of lights on the dashboard of all modern cars light up. At this stage we are particularly interested in two.
The first is the oil pressure warning light, the second is the battery recharging indicator light, which indicates that the generator is ready to start working after the engine is started. Both of them should glow bright red when the ignition is on, even before the engine starts. And if one of them does not light? If the recharge light does not light, it is half the trouble, but if the emergency oil pressure light does not light, it is an alarm bell. Be careful, you have lost control over the lubrication system! Engine oil pressure is the main indicator of the unit's serviceability. Without monitoring the oil pressure, you risk having to undergo a major engine overhaul with all the ensuing consequences.
The cause of the malfunction is either poor contact between the terminal and the sensor, or in the sensor itself. As a rule, you should look for the sensor in the area of the oil filter. The malfunction needs to be fixed. Only after you have made sure that everything is in order, start the engine.
"Cold" start
A working engine with well-adjusted fuel and ignition systems and a working battery starts in one attempt within 3-5 seconds. Consistently occurring problems with "cold" starting indicate malfunctions. Let's assume we avoided this and the engine started...
Let's look at the instrument panel. The two lights mentioned above should go out.
Caution: If the oil pressure light remains on for 5 seconds, stop the engine!
After a few minutes, try starting the engine again. If there is no oil pressure, you need to look for the cause of the problem.
Possible causes: low oil level, faulty oil pressure sensor; the oil pump oil receiver mesh is clogged; the oil pump is faulty; severe wear of the main and connecting rod bearings of the crankshaft.
If the oil pressure is OK, we proceed to inspect the engine in warm-up mode.
Warming up the engine
The speed of a cold engine is approximately 1.5 times higher than the rated idle speed, which is usually 700-900 rpm, and should gradually decrease as the engine temperature rises.
After 7-10 minutes from the start, the engine temperature should reach a level of about 80°C and stabilize (as well as idle speed).
If your car is equipped with a tachometer and a dial gauge showing the coolant temperature, this process is easy to monitor.
When warming up occurs according to the above scenario, the idle system and engine cooling system operate normally.
If the engine temperature does not reach the required level, the thermostat valve is most likely to blame. There are many more reasons for engine overheating and they are reflected in the technical reference.
Once the engine has warmed up sufficiently and the idle speed has stabilized (you will find out about this from the readings of the control devices), it's time to listen to the engine sing.
A beautiful, sonorous voice means a healthy body
Doctors assure that this statement is completely true in relation to humans. The same can be said about the engine.
A functioning engine makes a steady hum and "ticks" like a clock. Some mechanics say that it "whispers." Despite the figurativeness of the expressions, you probably understand what they mean.
If the engine runs unevenly, with failures, periodically vibrates, know: this indicates its malfunction. Sometimes malfunctions are a consequence of wear of engine parts and a drop in compression in the cylinders, but most often the causes are leaks in the intake tract, a clogged air filter, malfunctions in the ignition system and fuel system. I would like to dwell on those cases when the engine, as they say, "runs rough", that is, one of the cylinders does not work.
Using the method of alternately disconnecting the high-voltage wires from the spark plugs, it is not difficult to find the "saboteur". Once you get to. faulty cylinder, the engine's operating characteristics will not change.
Often the cause of the malfunction can be determined by inspecting the spark plug. This allows you to learn a lot of interesting things about the condition of the engine.
It is impossible not to mention extraneous noises and knocks. Let us immediately stipulate that this diagnostic method is a "high-end skill" and is not within the capabilities of all professionals.
Car enthusiasts should keep in mind that any sharp metallic sounds indicate a malfunction. If they are "produced" by mounted units (generator, pump, power steering) - that's not so bad. You can determine the "culprit" of the noise by successively removing the drive belts of these units. If the extraneous sound disappears after removing the next belt, shake the corresponding pulley to determine the radial and axial play of the bearings. More often than not, they are the ones who trouble the peace.
Much greater trouble comes from knocking sounds coming from the belly of the engine itself. They are listened to in various engine operating modes using a car stethoscope or, if there is none, a dry stick with a diameter of about 10 mm made of hard wood (it is pressed to the cheekbone below the earlobe). In this way, it is possible to identify defects in the gas distribution mechanism, cylinder-piston group, and crank mechanism.
Let us emphasize once again that in order to make a diagnosis, musical ear is not enough; you need to have professional experience and excellent knowledge of the "matter part".
A healthy mind resides in a healthy body
A diagnostic examination would be incomplete without an analysis of the vehicle's exhaust smoke. It's already warmed up enough, so it's time to go to its "sirloin" and look under the horse's tail.
The exhaust from a healthy engine is virtually colorless. A barely noticeable light white smoke comes out of the exhaust pipe, the intensity of which increases when you press the gas pedal sharply.
In frosty weather, a properly functioning car leaves behind quite thick clouds of white steam (not to be confused with smoke!), indicating complete combustion of the fuel.
Inhaling exhaust fumes for a long time is not good for you. We turn off the engine. But this is not the end yet. It is worth examining the inner surface of the oil filler cap. The presence of traces of dirty yellow foamed emulsion on it is a very alarming symptom, indicating that antifreeze is leaking into the oil. After removing the cap of the expansion tank or radiator, inspect the antifreeze. Warning: to avoid injury, do this on a cooled engine! An oil film on the surface of the antifreeze, as well as foamed motor oil, are harbingers of urgent engine repair.
Well, that's probably all. We examined the "patient" completely, literally from the tip of his nose to his tail. And during the inspection they did not use expensive equipment that was inaccessible to most car enthusiasts, but what was given to us by nature: sight, hearing, smell and, of course, the mysterious "gray matter".
Exhaust smoke analysis
An oily ring-shaped band 6-8 mm wide on the outer surface of the vehicle's exhaust pipe ("mourning ring") is a consequence of increased oil consumption. A major engine overhaul is inevitable.
The smoke is black. Sign of incomplete combustion of fuel. The fuel system produces a very rich mixture and needs adjustment.
Smoke of blue (purple) shade. Sign of increased oil consumption. The engine requires replacement of oil seals or repair of the cylinder-piston group.
Thick white smoke. Sign of a burnt out cylinder head gasket. The coolant enters the combustion chamber.
Smoke with the smell of exhaust gases from the removed pipe of the crankcase ventilation system (breather) of the engine. A sign of exhaust gas breakthrough into the oil pan due to increased clearances in the cylinder-piston group.
(You will find the original on the portal: HONDABOOK.ru)