If the engine overheats during operation or warms up slowly to operating temperature, you need to check the thermostat
To check the thermostat on the car, start the engine and touch the lower radiator hose with your hand. It should be cold.
After the coolant temperature reaches 87-92 °C, the hose should start to heat up, this indicates that the cooling liquid has begun to circulate through the radiator.
If this does not happen, you need to remove the thermostat and check its operability.
Preparing the car for the job.
Drain the coolant (see the article - Checking and replacing the coolant of the Nissan Almera engine)
Without removing the hoses from the nozzles of the thermostat cover, unscrew the three bolts of fixing the thermostat cover with the head by 10
We remove the cover together with the hoses from the thermostat housing
Removing the thermostat from the housing
The thermostat connection is sealed with a rubber gasket.
To check the thermostat, we lower it into a vessel with water.
We heat the vessel and control the beginning of the valve opening by the thermometer.
The valve stem should start to extend at a temperature of 89 C, as indicated by the number 89 on the thermostat flange
At a temperature of 95 ± 2 C, the valve must fully open – the stroke of the stem is not less than 8 mm.
We install the thermostat in reverse order.
We top up the coolant to the norm and check the tightness.
Removing the thermostat housing
The thermostat housing is removed during engine overhaul or when a leak appears between the head and the flange of the thermostat housing.
Drain the coolant (see the article - Checking and replacing the coolant of the Nissan Almera engine)
Removing the air intake and resonator
We remove the hoses of the cooling system from the holder 1, fixed on the bracket 2
Remove the holder 1 of the cooling system hoses from the holes of the bracket.
Having squeezed the ends of the clamp 2, we move the clamp along the hose and remove the heater hose from the nozzle of the thermostat housing
We also disconnect the radiator inlet hose 1 and the steam outlet hose 2 from the thermostat cover nozzles.
Unscrew the mounting bolt of the hose holder bracket by 10 with the head
Removing the bracket
Unscrew the nine bolts securing the thermostat housing to the cylinder head with the head by 8
The front lower mounting bolt of the thermostat housing is the longest of the nine bolts
Removing the thermostat housing
Removing the gasket
There are cavities for oil and coolant in the housing and gasket
Install a new gasket and tighten the bolts in the sequence shown in Figure 7. The tightening torque is 10 Nm.
Fill in the coolant.
The coolant level should be above the min mark (approximately in the middle between min and max).
We check the operation of the thermostat.
We start the engine and set the RPM to about 1500 -1.
When the thermostat is activated, the upper radiator hose must be hot.
We monitor the engine temperature readings.
If the radiator fan is running and the upper radiator hose is hot, this indicates that our thermostat has opened.
Check the coolant level again.