Nissan Maxima QX

since 1993 of release

Repair and car operation

Nissan Maxima QX
+ Nissan Maxima brand Cars
+ Maintenance instruction
+ Settings and routine maintenance
- Engine
   + SOHC Engines
   + DOHC Engines
   - General major maintenance of the engine
      General information
      Check of pressure of oil
      Check of kompressionny pressure in cylinders
      Diagnostics of a condition of the engine with use of the vacuum gage
      Alternative versions of schemes of regenerative repair of the engine
      Removal of the power unit from the car - preparation and precautionary measures
      Removal and engine installation
      Order of dismantling of the engine by its preparation for major maintenance
      Dismantling of a head of cylinders
      Cleaning and check of a condition of a head of cylinders
      Service of valves
      Assembly of a head of cylinders
      Removal of shatunno-piston assemblies
      Removal of a cranked shaft
      Cleaning of the block of the engine
      Check of a condition of the block
      Honingovaniye of mirrors of cylinders
      Check of a condition of components of shatunno-piston group
      Check of a condition of a cranked shaft
      Check of a condition and selection of loose leaves of radical and shatunny bearings of a cranked shaft
      Check of a condition of camshafts, pushers of valves and bearings
      Engine assembly order
      Installation of piston rings
      Installation of a cranked shaft and check of working gaps of radical bearings
      Installation of a back epiploon of a cranked shaft
      Installation of shatunno-piston assemblies and check of size of working gaps in shatunny bearings of a cranked shaft
      Trial start and engine running in after major maintenance
+ Systems of cooling, heating
+ Power supply system and release
+ engine Electric equipment
+ Control systems of the engine
+ Transmission
+ Coupling and power shafts
+ Brake system
+ Suspension bracket and steering
+ Body
+ Onboard electric equipment


General major maintenance of the engine

General information

In this Part of Head descriptions of procedures of removal and installation of the power unit, and also the general major maintenance of a head of cylinders and internal components of the engine are placed.

Brought to attention of readers the material contains a wide range of information - from a practical advice on acquisition of necessary spare parts, to a detailed step-by-step statement of an order of performance of procedures of removal, check of a condition, regenerative repair and installation of internal components of the engine.

Descriptions of procedures are made on the basis of the assumption that the engine is completely removed from the car and is established on the assembly stand or a strong workbench. All information concerning procedures of repair of the engine, which performance it is possible without extraction of last of the car (in situ) it is provided in Parts SOHC Engines and DOHC Engines of the present Chapter.

Not always it is possible to define easily the moment when there is a need for carrying out major maintenance of the power unit. In attention the whole set of various factors should be accepted.

High run at all unessentially is a sign of that the engine needs major maintenance. On the other hand, also it is impossible to consider the insignificant period of operation as a sufficient guarantee of a working order of the power unit. Perhaps, the major factor defining service life of the engine, frequency and a regularity of performance of procedures of the general and routine maintenance of the car is. At normal leaving the engine will reliably serve throughout many and many thousand kilometers of run whereas the careless relation to performance of procedures of routine maintenance together with a negligent manner of driving can already result in need of performance of major maintenance of the power unit later very short term.

It is possible to consider an excessive consumption of engine oil as a signal about need of carrying out check of a condition of piston rings, maslootrazhatelny caps and/or directing plugs of valves. Naturally, first of all, it is necessary to make sure that losses of oil are not connected with development of its external leaks. Address for the help to the qualified expert who will help to define the general condition of the engine of your car on the basis of results of check of kompressionny pressure in cylinders (see. The section Check of kompressionny pressure in cylinders) and measurements of depth of depression at various initial parameters (see. The section Diagnostics of a condition of the engine with use of the vacuum gage).

Loss of the developed capacity, violation of stability of turns, excessive noise background of the klapanny mechanism, the increased fuel consumption usually are rather characteristic signs of need of performance of major maintenance of the engine, in particular, when all these factors are shown at the same time. If performance of a full range of settings does not help with elimination of the problems, carrying out the general mechanical works on engine restoration will be the unique way out.

Major maintenance of the power unit means recovery of all of its working parameters to level, characteristic for the new engine. During major maintenance replacement of piston rings and restoration of mirrors of cylinders (a pro-point and/or a honingovaniye) is without fail made. In case of performance of a pro-point of cylinders selection of pistons of the corresponding repair size is made. Replacement of radical and shatunny bearings is usually carried out, the pro-point and restoration of necks of a cranked shaft can be in case of need made. Service of the valves which condition at the moment of emergence of need for performance of major maintenance of the engine almost for certain leaves much to be desired is without fail carried out. In parallel with carrying out the general repair of the power unit also regenerative repair of such auxiliary components, as a starter and the generator is usually made. As a result of repair parameters of the engine come back to the values peculiar to the new unit, thus the last can serve smoothly still many and many thousands kilometers of run.

Such critical components of system of cooling as hoses, driving belts, the thermostat and the water pump at carrying out major maintenance of the engine SHOULD be replaced with the new without fail. Besides, it is necessary to check attentively a radiator condition (see. Head of System of cooling, heating). In case of identification of signs of development of leaks or passableness violation it is necessary to replace a radiator also. Many firm car repair shops do not give a guarantee on operation of the restored engine without performance of professional cleaning and radiator repair. Do not forget to check a condition of the oil pump also.

Before starting performance of major maintenance of the engine, attentively familiarize with materials of the real Part of Head for the purpose of theoretical preparation for the forthcoming work. Let's notice that major maintenance of the engine at all does not demand from the performer of high vocational training, however takes away a lot of time. It is necessary to plan refusal of using the car for the term of not less than two weeks, in particular in need of the request for the help in a mechanical workshop for the purpose of performance of separate recovery operations. Carry out small marketing, having checked existence on sale of required spare parts, tools and the equipment. Beforehand prepare all necessary materials. The most part of works can be executed with application of a usual set of the metalwork tool, however some of checks by determination of suitability of separate components to further use demand use of the precision measuring equipment. In doubtful situations address for the help to experts of a workshop of car-care center who always will help you to be defined with the decision on need of replacement or regenerative repair of any internal component of the engine.

Before giving any of details for carrying out regenerative repair to a car-care center workshop, carry out complete dismantling of the engine and all its internal components. Do not forget that a determinant in a question of expediency of performance of major maintenance of the engine is the condition of the block of its cylinders. Frequent cheaper and more reliably it appears to replace the worn-out engine restored. Never start acquisition of replaceable components until very carefully do not study a block condition. Remember that time is the main expensive factor at performance of major maintenance of the engine, and therefore, it is senseless to transfer it to installation of the worked well together or non-standard knots and components.

In summary we will notice that all efforts on performance of regenerative repair of worn-out components will appear spent for nothing at the negligent relation to the requirement of observance of purity at unit assembly.