Pic. 193. Parts of the thermostat housing and the thermostat itself: 1 - thermostat housing; 2 - a bolt with an internal hexagon, 10 Nm; 3 - thermostat; 4 - thermostat housing cover; 5 - a bolt with an internal hexagon, 10 Nm; 6 - O-shaped sealing ring; 7 - housing cover; 8 - temperature switch (turning off the air conditioner and the third stage of the fan), black color; 9 - temperature sensor of the Motronic injection system, blue; 10 - temperature sensor for turning on the fan of the engine cooling mode after it stops, yellow; 11 - collar
Thermostat 3 (pic. 193) is located in a separate thermostat housing 1, in which, in addition to the thermostat, there are two temperature sensors: a coolant temperature sensor 9 and a sensor 10 for turning on the cooling system fan when the engine is not running.
It is somewhat unusual to mount three temperature sensors in the thermostat housing. They are not screwed, but are fastened with spring clips, which must be opened with a screwdriver in case of removing the sensors. The temperature sensors have O-ring seals to ensure the required tightness. Plug sockets, if they are disconnected, cannot be mixed up, as they are of different colors; the coolant temperature sensor has a two-pin connector, and the coolant fan on when the engine is off sensor has a four-pin connector.
The thermostat is located under the cover 4 (to which the hose is attached) with O-ring 6.
Remove the VR6 engine thermostat as follows:
- open the cover of the expansion tank;
- drain the coolant to at least the level of the thermostat setting (approx. 4 liters of coolant);
- disconnect the hose from the thermostat cover and remove the cover;
- remove the thermostat.
The thermostat cannot be repaired, and therefore, if it malfunctions, it must be replaced.
Checking the operation of the thermostat is carried out in exactly the same way as for the thermostat of a 2.0-liter engine. A defective thermostat should be replaced.
When installing a thermostat:
- use a new sealing ring;
- check the hose clamp before tightening it back on the hose;
- Pour coolant into the cooling system.
If parts were removed from the thermostat housing, then when installing them, observe the following recommendations:
- install the thermostat housing with a new sealing ring on the engine and tighten the long bolts 2 (top, see fig. 193) torque 10 Nm;
- if the housing cover 7 and the coolant pipeline were removed, be sure to replace their sealing rings. Insert the coolant pipe tightly into the cover and tighten the bolts 2 fastening (below, see fig. 193) covers torque 10 Nm;
- if temperature sensors 9 and 10 were removed, install new O-rings, insert the appropriate sensor and slide the spring clip over it;
Note. The spring clip must be firmly seated, otherwise the connection will not be airtight.
- If the coolant line has been removed, new O-rings must be fitted to both ends of the line.
Visitor comments