Infiniti QX4 service since 1996 of release
1. Introduction
2. Maintenance instruction
3. Routine maintenance
4. Engine
5. Cooling and heating systems
5.1. Specifications
5.2. Antifreeze - general information
5.3. Service of system of cooling
5.4. Removal, installation and check of serviceability of functioning of the thermostat
5.5. Removal, regenerative repair and installation of a radiator of system of cooling
5.6. Replacement of the water pump
5.7. Removal and installation of the fan of system of cooling
5.8. Air lines of distribution of air submitted to salon
5.9. System of automatic air conditioning – a design and a functioning principle
5.10. Design of a refrigerator path of central air of air
5.11. The To/in compressor, - the general information and a functioning principle
5.12. A receiver dehumidifier - the general information and service
5.13. Check of serviceability of functioning and service of systems of heating and air conditioning
5.14. Diagnostics of central air of air
6. Power supply systems and managements
7. Start and charge systems
8. Transmission line
9. Brake system
10. Suspension bracket and steering
11. Body
12. Electric equipment



5.4. Removal, installation and check of serviceability of functioning of the thermostat

Before finally affirming as opinion on a thermostat exit out of operation, check level of cooling liquid in system, a condition and effort of a tension of belts of a drive of auxiliary units (see. Head Routine maintenance), and also serviceability of functioning of a measuring instrument of temperature.

One of possible the reason of too slow warming up of the engine (according to measuring instrument indications) is thermostat jamming in open situation — replace the thermostat new.

In case of an overheat of the engine touch a hand the top hose of a radiator. If the hose is not heated up, possibly, the thermostat is jammed in a closed position, blocking circulation of cooling liquid through a radiator. Replace the thermostat.

At all do not maintain the car with the removed thermostat! Control system feedback that will lead to increase of toxicity of the fulfilled gases and excessive increase in fuel consumption thus can become torn.

If the top hose is heated up, it means that cooling liquid regularly circulates through a radiator, i.e. the thermostat is open (see. Diagnostics of malfunctions of knots and car systems, Diagnostics of malfunctions of system of cooling).

Thermostat check on a workbench (see below) gives the most exact results.



  1. Disconnect a negative wire from the battery.
  2. Empty cooling system (see. Head Routine maintenance) — if replacement of a mix was made recently, keep it for further use.
  3. Walk on the top radiatorny hose to the engine and find a cover of a casing of the thermostat.
  4. Weaken a collar and remove a hose from the connecting branch pipe. If the hose "became attached", grasp it nippers (as it is possible closer to a cut) and try повращать on a branch pipe for the purpose of destruction of a holding layer of deposits. The old hose subject to replacement can be cut simply (try not to scratch a branch pipe).
  5. If the surface of a branch pipe contacting to a hose is struck with corrosion, or mechanically damaged, it is meaningful to replace a cover of a casing of the thermostat.
  1. Turn out fixing bolts and uncover a thermostat casing. If the cover "became attached", обстучите its hammer with soft the brisk. Prepare for collecting spilled liquid.
  1. Try to remember adjusting position of the thermostat (a klapanny finger up), then take it from a casing.
  1. Remove from casing and cover surfaces all traces of hermetic and a material of old laying.
  2. Replace rubber sealing laying of a cover of the thermostat.
  1. Establish the thermostat in a casing (do not apply any hermetic). Track, that it appeared is developed by a pumping finger up, and the equipped spring the party to the engine.
  1. Establish into place a cover and fix it bolts, having tightened the last with demanded effort.
  2. Connect to a cover branch pipe a hose and strongly fix it a collar. Return into place all components acting in film for the purpose of ensuring access.
  3. Fill in in system necessary amount of cooling liquid (see. Head Routine maintenance).
  4. Start the engine and check it on existence of leaks and serviceability of functioning of the thermostat (see above).

Check on a workbench


  1. Remove the thermostat from the engine (see. Head Engine).
  1. Tie up to thermostat assembly a piece of a wire and lower it in the capacity filled with water. There lower the thermometer.

Track, that the thermometer and the thermostat did not adjoin to walls and a capacity bottom!

  1. Start to warm up slowly water, watching change of indications of the thermometer — operation of the valve of the thermostat should occur in strict accordance with requirements of Specifications.
  1. Estimate size of complete opening of the valve — the nominal rate makes b — and = 8 mm.

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5.3. Service of system of cooling
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5.5. Removal, regenerative repair and installation of a radiator of system of cooling