HEXA

ENGINE

Components :

a) Radiator :

The radiator used in ARIA is of cross flow type.

The radiator is a heat exchanger used to dissipate

the coolant heat. A radiator fan is used to create

forced air circulation.

Radiator consists of radiator core, inlet tank and

an outlet tank.

Cores are usually made of aluminum. The core

has two sets of passages, a set of tubes and a set

of fins attached to the tubes. The tubes run from

inlet tank to outlet tank. Coolant flows through the

tubes and air flows between the fins. The

atmospheric air passing between the fins carries

away the heat, which lowers the temperature of

the coolant.

b) Thermostat :

It is located in a housing provided for it in the

Engine block

The thermostat controls the flow of coolant as

follows.

1. During a cold start, thermostat does not allow

coolant to flow to radiator since it is closed;

instead the coolant flows through thermostat

bypass outlet back to the engine .Thus short

circuiting of radiator which helps in attaining

engine working temperature in a very short

period.

2. As soon as the coolant temperature reaches

the opening temperature of the thermostat, the

thermostat valve starts opening gradually and

coolant starts flowing to the radiator. At the

same time the 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. In this

condition maximum quantity of engine coolant

flows from radiator to water pump.

Specifications



Thermostat start open temperature is 87º±2ºC

at 0.1mm travel.



Full open temperature is 98º±2º C at 8.0 mm

(Min.) travel.



Leakage through main valve (including jiggle

pin) at room temperature and 1 kg/cm

150cc/min.



Main flow rate of 165 LPM at 1.4 bar back

pressure.

Satisfactory operation of thermostat is very

much essential for:



Efficient engine operation



Longer engine life.

Checking procedure of thermostat:

1. Remove thermostat element from the

housing.

2. Mount thermostat element in a suitable fixture

and place the fixture in a vessel filled with

water.

3. Fix dial gauge with its spindle on valve

surface with a pretension of 0.5mm

4. Heat the vessel and measure the water

temperature with proper thermometer.

5. Note down the temperature when dial gauge

needles starts moving indicating valve

opening.

6. Note down the water temperature for needle

movement

(for valve fully open position).

7. The opening temperature and fully open

temperature as measured should be as per

the mentioned specifications.