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5.2. Removal, check of functioning and installation of the thermostat

Performance of the check described below will require the thermometer.

Removal

 PERFORMANCE ORDER

  1. Disconnect a negative wire from the battery.
  2. Empty the cooling system.
  3. Disconnect a radiator hose from a thermostat casing.
  4. On models of 4.2 l disconnect from a casing of the thermostat perepuskny a hose (components of the thermostat of models of 4.2 l are shown on an accompanying illustration).
1 — the thermostat
2 — laying
3 — a casing
4 — bolts
  1. Give bolts of fastening of a casing of the thermostat to the engine.
  2. Remove a casing and take the thermostat from the engine.

Check of serviceability of functioning

Visual check most often appears enough for definition of serviceability of its functioning. For example, the thermostat removed from the cold engine with completely open valve no doubt is faulty and is subject to replacement.


 PERFORMANCE ORDER

  1. Make sure that in a cold state the valve of the thermostat is closed and reliably pressed by a spring.
  2. Tie up the thermostat to a wire and lower together with the reliable thermometer in a vessel with cold water. Track that neither the thermostat, nor the thermometer adjoined to walls and a bottom of a vessel (see an accompanying illustration).
1 — the vessel filled with water
2 — the thermostat
3 — cross laid level
4 — a wire
5 — the thermometer
6 — wooden laying
7 — heat source
  1. Begin to heat slowly water in a vessel, monitoring indications of the thermometer. Write down the indication at the time of the beginning of opening of the valve of the thermostat.
  2. Continue to heat water to full opening of the valve, measure height of lifting of a plate of the valve over a saddle. Compare results of measurements of temperature and height of opening of the valve to standard requirements (see size tables and adjustments at the end of the Management). At an exit them out of admissible limits replace the thermostat.

Installation

Installation is made upside-down.

 PERFORMANCE ORDER

  1. Track that all sealing surfaces were absolutely pure, without any traces of liquid sealant.
  2. Impose a pillow of sealant with a section of Ø of 2 ÷ of 3 mm on the condensed thermostat casing surface.
  3. Track that sealant was laid from the inside of bolted openings.
  4. Install a thermostat casing on the engine.

Special laying for installation under a thermostat casing is issued. Authors of this manual in order to avoid development of leaks recommend to use such laying without fail if the condition of the interfaced surface of a casing leaves much to be desired.

  1. Fill the cooling system with cooling liquid and check it for leaks.