DIY: Replace Engine Thermostat & Info

Thermostat plays an important role in maintaining the engine operating temperature as for engine, they need an ideal operating temperature in order for them working efficiently. How thermostats work for that? As the engine cold start, the thermostat valve will be closed, blocking the water flows to the radiator. Only after the engine warm and thermostat sensing the set point temperature, it will open the valve and allows the coolant to flows through the radiator for cooling up by the radiator fan or incoming air. The cooled coolant will be flow back to the engine block. Again, when the thermostat sensing cold coolant, it will close the valve and let the coolant circulate in the engine block until the temperature reached the set point before it open the valve for cooling.

What happen when the thermostat fails?

1.     Fail to open the valve - engine overheating if the thermostat fail to open the valve even though the coolant in the engine block boiling

2.     Fail to close the valve or without thermostat - Coolant will keep on flowing to the radiator and result to the engine fail to reach it ideal operating temperature that will result higher fuel consumption where Engine Control Unit (ECU) will send signal to rich up the fuel mix in order to get ideal temperature. For Vtec and MIVEC engine, low temperature mean that no Vtec/MIVEC. Vtec/MIVEC only function if engine in operating temperature. Beside that that, when cold start it will take time longer than before to warm up.

Alert with that, I decide to reinstall the thermostat with a new one. For five month, my perodua kancil cooling system work without thermostat after the mechanic removes it. He told me that this thing is "useless" after my car overheat because of failure thermostat. 

For this project, you will need

• New thermostat
• Thermostat housing gasket or gasket maker
• scrapper
• wrench no 12
• New coolant
• rack

I bought this thermostat with 82 degrees Celsius; RM45.00

Perodua Kancil Thermostat

First, drain the coolant. Draining point can be found below the radiator, refer picture below, with "mickey mouse ear" screw.

Draining screw in circle.

Draining  screw. Looks like "Mickey Mouse Ear"

Remove upper hose side at both sides; engine and radiator. For extra space, you can also remove distributor cover. 

Remove hose clamp as pointed in red arrow. You can also remove the distributor cover 

Using wrench no 12, remove two bolt of the thermostat housing. Clean it up with water.

Left: Thermostat housing, Right: Thermostat



Thermostat hole at the engine block

I forgot to buy the thermostat housing gasket, but luckily I have this; Gasket Maker



Black in color Gasket Maker

Install the thermostat like this.

Place the gasket maker around the surface that will be linked to engine block.

I have to wait for 10 minutes before the thermostat can be assembled, as per directions given by the Gasket Maker manufacturer. If you using paper gasket, you can assemble it instantly. Tighten the bolt and reattach the radiator hose and distributor cover. Refill the radiator with coolant start engine and checks for any leaking. Add some more coolant in the radiator until it full. Done!

Click HERE on how to check the thermostat