Service Infiniti QX4 since 1996 of release
1. Introduction
2. The maintenance instruction
3. Routine maintenance
4. The engine
5. Cooling and heating systems
5.1. Specifications
5.2. Antifreeze - the general data
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 an automatic air conditioning – a design and a functioning principle
5.10. A design of a refrigerator path of a central air of air
5.11. Compressor K/V, - the general information and a functioning principle
5.12. The Receiver-dehumidifier - the general information and service
5.13. Check of serviceability of functioning and service of systems of heating and an air conditioning
5.14. Diagnostics of a central air of air
6. Power supply systems and managements
7. Start and charge systems
8. A transmissionnaja line
9. Brake system
10. A suspension bracket and a steering
11. A body
12. An electric equipment


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

Before definitively to affirm as opinion on a thermostat exit out of operation, check up level of a cooling liquid in system, a condition and effort of a tension of belts of a drive of auxiliary units (Routine maintenance see the Head), 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 position, — replace the thermostat new.

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

At all do not maintain the car with the removed thermostat! Thus the control system feedback that will lead to increase of toxicity of the fulfilled gases and excessive increase in the expense of fuel can be broken off.

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

The most exact results are given by thermostat check on a workbench (see more low).



  1. Disconnect a negative wire from the battery.
  2. Empty cooling system (Routine maintenance see the Head), — if mix replacement was made recently, keep it for the further use.
  3. Walk on top радиаторному to a hose to the engine and find a cover of a casing of the thermostat.
  4. Ослабьте a collar also remove a hose from the connecting branch pipe. If the hose "has become attached", grasp it nippers (as it is possible more close to a cut) and try повращать on a branch pipe for the purpose of destruction of a keeping layer of adjournment. 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 amazed by corrosion, or mechanically damaged, it makes sense to replace a cover of a casing of the thermostat.
  1. Turn out fixing bolts and uncover a thermostat casing. If the cover "has become attached", обстучите its hammer with soft the brisk. Prepare for gathering of a spilt liquid.
  1. Try to remember adjusting position of the thermostat (клапанным a finger upwards), then take it from a casing.
  1. Remove from casing and cover surfaces all traces of hermetic and a material of an old lining.
  2. Replace a rubber sealing lining of a cover of the thermostat.
  1. Establish the thermostat in a casing (do not apply any hermetic). Track, that it has appeared is developed a prorolling finger upwards, and the equipped spring the party to the engine.
  1. Establish into place a cover and fix its bolts, having tightened the last with demanded effort.
  2. Connect to a branch pipe of a cover a hose and strongly fix its collar. Return into place all components acting in film for the purpose of providing of access.
  3. Fill in in system necessary quantity of a cooling liquid (Routine maintenance see the Head).
  4. Start the engine and check up it on presence of leaks and serviceability of functioning of the thermostat (see above).

Check on a workbench


  1. Remove the thermostat from the engine (the Engine see the Head).
  1. Tie up to assemblage of the thermostat 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 exact conformity to requirements of Specifications.
  1. Estimate size of full opening of the valve, — the rating value makes b—а = 8 mm.

On page back
5.3. Service of system of cooling
On the following page
5.5. Removal, regenerative repair and installation of a radiator of system of cooling