87
ENGINE2.2LDICOR
Fig. 193
Fig. 194
Water Pump
(Fig. 193)
Check water pump for free rotation. Check water
pump for flow rate at specified rpm. Check for water
leakage through leakage hole. It indicates that water
seal is damaged and leaking. Replace the water pump
if necessary.
For water pump removal and fitment procedure please
refer engineoverhaul section.
Pump flow rate 165 lpm at 4000 rpm against the back
pressure at 1.4 bar.
Thermostat
(Fig. 194)
Thermostat is installed in cooling system between
radiator outlet & the water pump.
Working principle of thermostat
1. For cold engine (immediately after starting) :
Thermostat does not allow coolant to flow toWater
pump (Thermostat valve in closed position)
instead coolant flows from radiator bypass pipe
to engine. This helps for attaining engine working
temperature in a very short period.
2. As soon as the coolant temperature reaches
opening temperature of thermostat, the
thermostat valve starts opening gradually and
coolant flow starts from radiator to water pump.
At the same time thermostat by pass starts closing
gradually.
3. As the engine working temperature reaches
thermostat full open temperature, the thermostat
valve opens fully and thermostat by-pass valve
closes completely. Under such conditionmaximum
quantity of engine coolant flows from radiator to
water pump.
l
Thermostat Start opening temperature : 87ºC
l
Full open temperature : 98ºC
l
Leakage through main valve (including seepage
hole) at room temperature and pressure of 1 kg/
cm2 is 10 Liters/hr.
l
Maximum leakage through by pass at full open
temperature or main flow rate of 165 lpm is 1.5
Liters/minute.




