According to the proverb, people are met by their clothes and seen by their minds. Cars before buying are also first evaluated by clothes: by the body and the way it looks. And then they look at the mind, and in our case this mind will be the engine (although many people think that the engine is the heart. Let everyone be right). Let’s see by what signs you can at least approximately assess the condition of the motor.
The eye is a diamond
Unfortunately, a person has neither X-ray vision, nor even a simple diagnostic scanner in his body. All this complicates the procedure of assessing the condition of the motor, so the inspection with eyes alone cannot be considered final and decisive. Consequently, do not think that a detailed and careful inspection with preliminary reading of specialized forums can replace diagnosis. It is not.
Therefore, everything described below should only precede the diagnosis, especially if we are talking about an expensive or complex car. And the inspection we are going to talk about is only able to reject initially unsuitable variants, with which there is no sense to bother further. So the eye is good, but it is often impossible to do without further diagnostics. What can be advised from instrumental methods, we will tell you at the end of the material. And now – one more disclaimer.
Predictably problematic motors
Unfortunately, there are motors (and even cars) that are already famous for their problems. Therefore, think carefully whether you need in principle a car with an engine, for example, EP6 Prince (it is equipped with most of the cars Peugeot and Citroen after 2010) or Volkswagen EA111 1.4 TSI. All cars with unsuccessful motors have a competitor with a successful engine (and even a box) somewhere, so if as a result of studying the model you find a lot of complaints about the same problem, it is better to refuse such a car. However, this is already a question of philosophy, ethics and fetishism, so let’s close it for now.
The second thing you should pay attention to is typical faults, which are not terrible at all, but can serve as a reason for bargaining. For example, constantly flowing valve covers on some GM motors do not promise anything terrible, but allow you to drop at least a hundred when bargaining. It’s a small thing, but it’s nice.
In short, look for such small visible problems, which can be used as a basis for bargaining. But always remember: many more problems are usually invisible, and these are the real threats.
Nuances of inspection
Bring clean wipes and a flashlight. We will definitely need them. We start the inspection on a cold engine, so please do not start it until you arrive at the inspection site. Before starting the procedure, at least check the temperature with your hand: if the iron is not warm for the weather, the seller has already started to deceive. So, he has something to hide.
We open the hood lid and begin to thoughtfully examine the motor from the outside. And I would strongly advise not to ignore the widespread requirement to assess the degree of contamination of the motor. Of course, a motor nailed with dirt and age-old dust is a sad sight. Most likely, the owner of the car did not worry much about it, and repaired it only in case it suddenly stood up stubbornly. It is better not to dream that such a car was regularly serviced. And, of course, there is a probability that something regularly leaks from the engine (and maybe even gushes), and its cooling system in recent years is breathing on a candle. Or maybe it’s been driven through its wild green beauties by a ruthless hunter and fisherman who doesn’t care that this, for example, Kia Soul is not designed for off-roading at all. It could all be potentially dangerous, so it’s better to look at something else.
But a sparkling clean engine isn’t always a good thing either. It may have been under a layer of dirt three hours ago and washed to at least count the cylinders and give the correct information in the ad before the sale. But you can almost always see fresh leaks on a shiny motor. Well, at least there’s some benefit to it.
And now let’s see if this motor is not on the HBO, or if it was not before. In the first situation everything is simple: at least the metering unit, reducer or mixer can be seen. In the extreme case, it is impossible not to notice the gas cylinder in the trunk and the filling valve. If the HBO is dismantled, then traces can still be found, but not always.
So, let’s assume that the motor is moderately dusty (but not sugared to an extreme degree), there is no HBO (or there is, but it does not scare you), and the desire to inspect the motor is preserved in full. Then let’s begin.
What liquids will tell
So, look for the oil dipstick and pull it out into the light of day. Wipe it with a clean cloth, lower it again and look at the level. Above the middle but below the max mark is ideal. Level between min and max – very good. Above max and below min – very bad, I would give up the car at this stage.
Now let’s evaluate the condition of oil. No matter what forum experts say, it is very difficult to do it without a chemical laboratory. Therefore, it is practically useless to sniff and lick the dipstick, it is unlikely that the information obtained from these actions will give you anything.
It is much more interesting to look at the oil filler cap. From the inside it should be clean, deposits on it speak about the same deposits inside the valve cover, and this is a little more than just sadness. There can’t be any plaque on the cover. Scale is a sign of overheating or the fact of antifreeze getting into the oil due to a punctured cylinder-head gasket or a cracked block (but this is less common). It is quite possible that the motor has experienced significant overheating, and this is a definite evil.
There can be no foam in the oil or signs of fluid inhomogeneity. And the only thing you can see with your eyes is the color of the oil. Too dark is old, but do not think that it should be exceptionally transparent. Modern cleaning additives are so arranged that they collect deposits, as a result of which the oil can become darker. So things are not so clear here either.
On some cars with automatic transmission you can see a dipstick of the fluid in the automatic. It is not everywhere, and now it is more and more rare. And if you see it, pull it out safely. But there is a peculiarity here: on some cars there are marks that indicate the necessary level for cold and hot box, on others you can see it only on hot (in this case, there may be a mark on the dipstick, saying something about the temperature in the neighborhood of 55 ° C).
Now connect your developed sense of smell and sniff the dipstick at the full power of your lungs. The task is to catch the burning odor. If it is there, then most likely, the solenoids underpressure, frictions close not completely, slip and “burn”. As a rule, this is a prelude to a very expensive overhaul. You can consider that the car has no automatic transmission. It is up to you to refuse or demand a discount for overhaul or a second-hand unit for replacement.
If for some reason you doubt that you can correctly determine the oil level in the automatic transmission, look carefully at the dipstick: are there no bubbles in the oil? They can be formed from excess oil. And some especially gifted persons overfill it to increase the pressure in solenoids, lost due to contamination or deformation of the hydraulic block channels. If oil is bubbling, it means that there is something wrong with the automatic, and it is better not to buy this car.
Now look in the expansion tank. Antifreeze should be clean and without sediment. Precipitate is usually formed if technical genius of the owner decided to restore tightness of the cooling system with some miracle liquid. Miracles don’t happen, and no one knows what’s going on in the system, but it’s not good.
I know that you know, but I will repeat: the level of antifreeze in the tank should be between the maximum and minimum marks, and you should look it on a cold engine. And certainly do not try to unscrew the cap of the expansion tank on a hot engine, it is dangerous.
Now all that is left is to look at the level of fluids in the hydraulic fluid reservoir, in the brake and clutch reservoirs (if any). At the same time check the tanks for leaks.
What to look for on a cold engine
Oil has one peculiarity – like any liquid, it leaks. The main thing is that it should not leak where it should not. It is better to look for leaks twice: first before starting the engine, then – after a test drive. In the first case, you can climb with your hand with a flashlight and do not get burned, in the second case – once again to make sure that the abundantly flowing motor was not washed just before your arrival.
Depending on the motor design, leaks may or may not be noticeable. In any case, look at the valve cover gasket around the perimeter. Sometimes it is weak “by nature” and that is not fatal (but can be haggled over), but sometimes it can leak from too much crankcase gas pressure. This is unlikely, but possible.
Then if possible look at the camshaft oil seals (or one camshaft, but you can’t see them everywhere), the crankshaft pulley (you should also try). If dry – all is well, you can look further.
We look at all suspended (or “mounted”, here who likes to call it better) equipment. The pump should be dry, the generator should be clean, there should be no traces of oil or antifreeze on the equipment belts.
If possible, inspect the service belt for cracks, delamination, abrasions. To do this is most often difficult, but if you try, sometimes you can even twist it slightly and see the rivulets. In general, a neglected belt is not a fatal malfunction, but it helps to determine how much the owner complied with the regulations of TO, and whether you have to change the belt immediately after purchase.
At the same time, you can visually check the condition of the engine pads. There are visible cracks – bargain. Do not forget about the wiring. Wires should be laid in standard places, there should be no tape and twists. Here you can look at the battery terminals: if they are overgrown with oxide, the car was not well looked after.
If you are not lazy (and there should be no laziness), remove the air filter cover and look at it with an understanding eye. It is half a miracle if it is dirty. It is worse if there are traces of oil on it. Most likely, there is an excess of crankcase gases, and there is no assurance that the piston rings have not laid down many thousand kilometers ago.
Finally, it’s time to start the engine.
Look and listen!
Or rather, listen and look. Let’s assume that the starter worked at once, the start was confident. The engine did not “falter”, but immediately started smoothly. What to pay attention to?
First of all, a cold start will tell about problems in the timing mechanism. Admit it: you must have heard how “the valves knock”? In fact, of course, it is not them. Usually it is the cams of the camshaft that make the knocking noise when cold. This happens for one reason: incorrect clearance between the cam and the tappet. But here the situation is different.
First: a motor with hydrocompensators in the timing. In many cars in this case, small clicks in the first seconds after starting the engine are acceptable. But they should disappear quickly, much earlier than the motor warms up. Otherwise, you should be ready to replace the hydrocompensator (or several), and in neglected cases – rockers and even camshafts. And also should be concerned about the thought, why this “hydric” failed? Maybe the oil was changed once in 30 thousand? Or maybe the car has a mileage of not 50 thousand, as the seller says, but 250? This is also possible.
Situation two: there are no hydrocompensators (try to find out in advance, just google “Motor code + hydrocompensators”). Here it will be a little more complicated. Not all motors can boast of quiet operation until reaching operating temperature. Valve sound is then possible, but if it doesn’t go away as the temperature rises, it’s already wrong. Either the valves have never been adjusted, or irreversible phenomena in the timing gear have already started (see the previous paragraph). And of course you should be alarmed by a separate scratching valve: here, most likely, you will have to change the camshaft, and the mileage of the car is obviously under two hundred thousand.
And find out in advance, what way will have to adjust the valves on a particular motor without hydrocompensators. Slightly worse – by adjusting washers-spacers, and quite a torturous option – the lack of adjustment as such (then instead of it change the entire pushrods). Since the operation can be expensive, bargaining is very welcome.
On cars with phase shifters should be alerted to the crackling (or clicks) at cold start. If they are there (it is hard not to hear them, but you will have to exhale), then the phase shifter, most likely, has given its soul to God. We smile and bargain.
In general, the sound of a running motor should not have a separate sound. Background hum, tapping, clicking – this is usually not the norm.
And now it’s time for the good old “grandfather” test: when the engine is running, unscrew the oil filler cap. The cap should be slightly sucked to the neck, and oil should not fly from there. Excessive pressure under the cap indicates either a clogged recirculation valve or a worn piston group. In neglected cases, the oil dipstick may even be squeezed out. Here it is better not to bargain, and silently go away.
About the fact that it is desirable to look at the color and presence of exhaust, I will not remind you, it is quite elementary things.
What to do next?
Let’s assume that the obvious serious defects could not be identified. It is fine, but it does not mean that everything is all right with the engine. Still, all the most serious things are hidden inside, so it would be very good to conduct at least a minimum instrumental control.
The easiest thing to do is to measure compression. If you have a compressometer, then everything written above, you probably knew before. If you don’t have one, then find not only a device, but also a person who knows how to use it (strange, but this person is not always the owner of a compressometer). He will interpret the measurement results for you.
- There are two other good diagnostic methods. The first is endoscopy. Yes, with the help of a miniature camera on the “gut” you can see a lot of things. For example, scoring due to the remains of burnt catalyst in the cylinders. It is highly recommended for checking Korean Kia and Hyundai motors. The method has one significant disadvantage: a lot depends on the specialist who performs the endoscopy. It’s about the same as doing an ultrasound: you can see something for sure, but what exactly – not every doctor will tell you. Therefore, I would not really trust those who bought an endoscope (now this device can be bought in many online stores) and offers to see something. It is better to find a good service.
- The second way is a lick test. This is a check of the motor for leaks. In general, it is similar to compression measurement, but there are significant advantages. First, the results will be more accurate, and secondly, you can determine where exactly there is a malfunction. At least by the noise of escaping air: whistling in the air filter – skips through the intake valves, in the exhaust pipe – trouble with the exhaust valves, through the oil filler – piston rings are lodged or worn out.
Now all these procedures are not very expensive, however, they are not done everywhere. But if the car is not cheap, and its motor is known to be capricious, there is a sense in these tests.
Well, and, of course, it is desirable to carry out computer diagnostics. And not with ELM327 for 300 rubles from Aliexpress, and with the original scanner, better dealer.
If the motor is chain, and in addition, there is information about the short life of the chain itself or its tensioner, it is highly recommended to measure the timing of the timing to identify the implicit yet asynchronous. A scanner is not suitable for this purpose – you need an oscilloscope. Description of the procedure deserves a separate article.
In general, I will repeat once again: eyes and ears are great, but not enough to fully assess the condition of the engine. Therefore, with their help only discard the obviously unsuitable options, and with the rest – welcome to the diagnostics.
PS:
Lastly, I can not help but advise one more win-win method of diagnosing the motor, which is successfully used in their work by some resellers. Just stand and look carefully under the hood, gradually frowning more and more. Then transfer your gaze to the seller standing next to you. Lean more toward the engine, frowning. Look at the salesman again. Shake your head. An owner who knows there’s a problem may think you’re on to him and start making excuses. The simplest psychological technique often works, especially if the seller is not a worn-out “overbuyer”, but a morally unstable private citizen.