Cleaning Cooling System and Replacing Thermostatic Valve

CQ283680-UN-23DEC09

PY4158-UN-28AUG04

CQ283681-UN-23DEC09

For efficient operation, drain the used coolant, clean the system, replace thermostat valve and fill system again.

CAUTION: DO NOT REMOVE radiator cap or drain coolant until it is cool (see temperature indicator on instrument panel). Slowly loosen radiator cap and drain plug to release pressure.

1. Drain coolant, remove radiator cap (A). Open radiator drain valve (B) drain off engine coolant.

   IMPORTANT: Removal of thermostat valve is necessary for a complete cleaning.
2. Remove thermostat valve cap (C), remove valve and reinstall cap (without valve). Tighten cap screws to specification.

   Item	Measurement	Specification
   Thermostat Valve Cover Attaching Bolts	Torque	47 N·m (35 lb.-ft.)

3. Wash cooling system with water, close all drain valves/plugs and fill system with clean water. Run engine for approx. 10 minutes to loosen deposits of dirt and corrosion. Turn off engine and drain system water before corrosion and sediment settle again.
4. Clean the system with radiator cleaner, close all drain valves/plugs and fill cooling system with a good, commercial quality radiator cleaner and water. Follow instructions provided with cleaner. Turn off engine and drain system immediately.
5. Wash system with water, close all drain valves/plugs and fill system with clean water. Run engine for 10 minutes and then drain rinsing water.
6. Remove cover (C), remove gasket. Apply sealant to new gasket and install it with new thermostat valve. Install cover and tighten cap screws to specification.

   Item	Measurement	Specification
   Thermostat Valve Cover Attaching Bolts	Torque	47 N·m (35 lb.-ft.)

7. Fill with new coolant, close all drain valves/plugs and fill with clean water and coolant conditioner, as specified in "Fuel, Lubricants, Coolant" section.
8. Check coolant level — fill radiator to upper part of filler neck and expansion tank to "LOW" mark. Operate engine until working temperature is reached. Wait for engine to cool down (preferably all night) and check coolant level again. With cold engine, coolant level should be at "LOW" mark. With engine at operating temperature, the level should reach "FULL" mark (high). When replacing coolant it may be necessary to fill up a few times, before system coolant level is stabilized. Add coolant to expansion tank, until correct level is attained.

NOTE: Radiator cap is responsible for keeping the cooling system pressurized. Check condition of seal. Replace cap if necessary.