Whether diagnostics and if yes, that for what it is carried out is necessary in general?
The engine is a difficult mechanism which can long and smoothly work only at appropriate leaving. To be sure that all its systems are in good repair, as well as for the purpose of prevention, it is necessary through certain periods or run of the car to carry out diagnostics of the engine.
General diagnostics of the engine
Usually at the person the occasion to address on inspection arises, as a rule, only when us starts something disturbing seriously. There is a wish to focus the attention on the word "seriously" as often it can appear too late.
Something somewhere pinned up, slightly was ill, released – and forgot, and after all the reason why it occurred is not clear sometimes and whether will pull it further more serious consequences. But to learn that actually happens to an organism and in what it a state, it is necessary to pass full inspection.
Absolutely same happens and to the engine, to only that difference that it cannot report to us about it. Though many modern cars are equipped with systems of self-diagnostics which results are output to displays of saloon monitors. But it so far only the prerogative and is removed only small percent of information there, and most of motorists have to watch operation of the engine.
The general diagnostics of the engine begins with its survey. The serviceable engine has to be absolutely dry, apart from traces of the dirty potek which got from a roadbed. At serviceable shatunno-piston group the engine works silently, trouble-free, and the exhaust of the muffler is almost imperceptible. The main indicators of its work, such as and waste of oil, are in norm.
At survey traces of oil or cooling liquid are not allowed. For better diagnostics the engine has to be washed up.
The wash of the engine is necessary not only from the esthetic point of view, but also as observance of technical parameter for its normal work. The dirty engine takes away heat, and so worse, it influences temperature condition of the engine and its state in general.
If the speech came about temperature condition of the engine, we will stop at once on diagnosing of serviceability of the cooling system which is responsible for it and of which the big percent of refusals is the share.
Malfunction of the cooling system of the engine
All branch pipes of cooling should not have traces of damages, collars at their edges have to be guaranteed tightened and there should not be traces of dribbles anywhere.
Let's remind. After start of the engine cooling liquid circulates only in a shirt of cooling of the engine and a radiator of an oven that it is easy to determine by fast intake of warm air in salon of the car in the winter.
In process of warming up the valve of the thermostat is partially slightly opened (58-64 degrees) and the part of liquid gets to a cooling radiator where having given the part is warm, comes back to a shirt of cooling of the engine. When temperature of cooling liquid comes nearer to 95-98 degrees, the valve of the thermostat opens completely and all liquid starts circulating through a radiator, being cooled thus. Along with opening of the valve in the same temperature range the electric fan of cooling of a radiator turns on that too promotes decrease in temperature of cooling liquid.
If this temperature condition is not observed, intervention in operation of the cooling system as at an overheat of the engine there can come serious consequences which will demand expensive repair is required.
Not operation of the electric fan of the cooling system can be connected with burn-out of a safety lock, the electric motor or failure of the sensor of temperature. At the idle sensor it is possible to connect among themselves the wires going on it that at inclusion of ignition to force it to work in the compulsory mode. It will be enough independently to reach garage and not to overheat the engine.
On the cars supplied viskomufty (the device bringing the fan into work when heating) the fan of cooling of a radiator, at its refusal engine temperature also increases. In these cases for work restoration the viskomufta needs to be jammed in any available way.
Not eliminated temperature increase can lead to breakdown of laying of a head of the block and an exit of the engine out of operation. At laying breakdown temperature in the engine starts growing in a geometrical progression that conducts to a progar of valves, pistons and an engine wedge.
And the reason of similar emergencies often lies above and is sometimes visible an unaided look. It can be the branch pipe which is simply undermining initially, because of not held on collar which is capable to come off on the way a branch pipe once that will bring to instant loss of cooling liquid. If not to notice it (keen conversation, fatigue or simply a carelessness to indications of devices in time, and sometimes and their refusal), not to avoid an emergency.
Mirsovetov it is useful for readers to know that in the cooling system of the engine it is considered one of the most widespread malfunctions jamming of the thermostat in a closed position. Liquid in this case cannot get to a radiator of cooling and there is an engine overheat.
It is easy to diagnose the faulty thermostat a simple touch of a hand to its bottom. At the serviceable thermostat and completely heated-up engine the bottom of the thermostat has to have temperature of the top tank of a radiator, i.e. to be we heat. If a bottom cold or warmish, the thermostat it is necessary to replace.
As the reason of an overheat wear and malfunction of the pump of cooling liquid can often serve (pomp). When rocking for a pump pulley, there should not be a noticeable side play. At dribble of the pump the amount of cooling liquid that conducts to temperature increase of the engine decreases. In the winter it is well noticeable by bad warming up of salon because of decrease in efficiency of a heater.
The littered honeycombs of a radiator of cooling that affects temperature increase of the engine, it is also possible to determine by colder sites of a radiator, after full warming up of the engine. A radiator if it copper, it is necessary to unsolder and wash out or replace with the new.
In the tight cooling system violation of operation of valves in a cover of a jellied mouth or a suction of air in connections can be the cause of an overheat. It conducts to loss of excessive pressure and boiling of cooling liquid as boiling temperature thus considerably decreases.
Also the air stopper when the cooling system is filled after repair or liquid replacement can be the cause of "boiling" of the engine. In these cases it is necessary to use the bypass valve for production of the air located, as a rule, in the most top point of the cooling system. On the engines which do not have such valve it is necessary to release the end of any branch pipe also in the most top point of system and after emergence of antifreeze, in a detachment place, to establish it into place.
At breakdown of laying of a head of the block cooling liquid starts getting to the pallet where mixes up with oil, forming an emulsion. It sharply worsens quality of oil and its ability to take away warmly from details and conducts to their fast overheat, and if not to take urgent measures, this situation usually comes to an end with emergency repair of the engine. The engine in these cases starts overheating literally in a few minutes after start.
Engine overheat, possible reasons
Besides malfunctions in the cooling system the overheat of the engine can occur and for other reasons.
It can be a crack in a block head, usually around a saddle of the final valve or support of a cam-shaft, as well as progar the most final valve that also causes an engine overheat. More rare, but nevertheless also cracks in the block of cylinders that it is possible to define visually when dismantling the engine or pressure testing under pressure meet.
At pressure drop in the lubrication system temperature condition of the engine as the oil supply to the rubbing surfaces worsens that we conduct to a local overheat of details and further their exit out of operation can also raise.
Pressure drop in the lubrication system can happen for a cause of defect of the oil pump, coking up of its oil receiver, the increased gaps in couples of friction or the filled-in , inappropriate on the viscous characteristic. Also it can be caused by hit of cooling liquid or not burned down fuel in the engine pallet. In carburetor engines hit of fuel can be caused because of breakdown of a membrane of a gasoline pump, and in injector or diesel engines – because of malfunction of nozzles.
The engine overheat is also influenced by failure of ignition or its nonprofessional installation that especially affects diesel motors, sensitive to it.
All told says that in time the carried-out diagnostics, can reveal a problem in its initial stage and relieve further of serious breakages and will help to keep your finance.
Diagnostics of the engine on noise
One of the responsible moments in diagnostics of the engine is a check of its working capacity on noise. The serviceable, correctly adjusted engine, works silently and steadily holds idling turns, and at increase in loading exactly, without failures gains steam, without making thus foreign sounds.
As it is known from the theory of mechanics, the sound is a gap. Gaps are provided practically for any mobile connections, otherwise they will jam when heating from own friction.
It is about the technological gaps provided by developers of the engine. As a rule, in the gap left by engineers when developing oil, for free rotation of details, prevention of zadir and branch from them of heat allocated during the work moves. The size of these gaps is very small and necessary only to hold there a portion of oil (an oil wedge) and so far in this gap there is an oil, connection works silently. Details cannot concern each other as between them there is an oil film. In process of wear of details the gap increases, and oil cannot keep in necessary quantity in the rubbing couple and a detail start working in contact with each other any more – from here a sound and, therefore, intensive wear.
If at once not to attach it significance, everything will end is very deplorable, working without oil (or with its insufficient quantity) details start heating up considerably that conducts to an inevitable emergency.
Similar situations do not arise, as a rule, at once, and first there is only an easy foreign sound that speaks about the problem which began somewhere in an engine subsoil. If to ignore this first signal which gives the engine the extraneous noise, then to it get used though it also starts amplifying, leaving it on "then".
At once to distinguish among the working engine details, the appeared foreign sound, readers of Mirsovetov need to remember a sound of the serviceable, purely working motor on the car. And knowing internal engine devices, it is possible to make a pre-trial detention about a source of a sound and to define degree of its danger.
So ringing, clinking sound, twice the smaller frequency of rotation, than turns of a cranked shaft, listened on all modes of the engine, usually proceeds from the increased gaps in valves.
Uniform knock, also with a smaller frequency of rotation, not depending on turns and loading of the engine usually proceeds from the valvate and distributive mechanism. It can be a worn-out camshaft, its bearings, a shaft of yokes, yokes and other details of the distributive mechanism.
The sharp knock idling listened on averages and high turns is connected with the beginning of destruction of a shatunny insert and its provorachivaniya in a rod cover.
The uniform knock coinciding with turns of a cranked shaft which amplifies at loading and warming up speaks about final fracture of a shatunny insert.
The same, but the sound "thumping" speaks about wear of radical inserts of a cranked shaft.
This list not full, it only covers the most often found malfunctions which can quite precisely be diagnosed on noise.
Any foreign sound revealed in the course of diagnostics should not be disregarded and it is necessary to take all possible measures for its elimination. It is easier to win against any illness when it is at an initial stage, than to wait for surgical intervention.