Cooling System: Diagnosis Honda S2000 AP1

Thermostat Test

Replace the thermostat if it is open at room temperature.

To test a closed thermostat

Scheme 1

1. Suspend the thermostat (A) in a container of water. Do not let the thermometer (B) touch the bottom of the hot container.
2. Heat the water and check the temperature with the thermometer. Check the temperature at which the thermostat first opens, and at which it is fully open.
3. Measure the lift height of the thermostat when it is fully open. Standard Thermostat Lift Height: Above 10.0 mm (0.39 in.) Starts Opening: 169-176°F (76-80°C) Fully Open: 194°F (90°C)

Scheme 2

Scheme 3

1. Loosen the water pump pulley bolts.
2. Remove the drive belt (see «DRIVE BELT REPLACEMENT»(ref-351946-S31110247242009122900000) ).
3. Remove the water pump pulley.
4. Turn the water pump counterclockwise. Check that it turns freely.
5. Check for signs of seal leakage. A small amount of "weeping" from the bleed holes (A) is normal.

Scheme 4

1. Drain the engine coolant (see «COOLANT REPLACEMENT»(ref-221326-S23165940062006022400000) ).
2. Loosen the water pump pulley bolts.
3. Remove the drive belt (see «DRIVE BELT REPLACEMENT»(ref-351946-S31110247242009122900000) ).
4. Remove the water pump pulley.
5. Remove the water pump (A) by removing the six bolts.
6. Clean and inspect the O-ring groove and the mating surface with the thermostat housing.
7. Install the water pump, with a new O-ring (B), in the reverse order of removal.
8. Refill the radiator with engine coolant, then bleed the air from the cooling system (see step 8 ).
9. Clean up any spilled engine coolant.

Scheme 5

Scheme 6

Scheme 7

Scheme 8

1. Start the engine. Set the heater temperature control dial to maximum heat, then turn off the ignition switch. Make sure the engine and radiator are cool to the touch.
2. Remove the radiator cap.
3. Loosen the drain plug (A), and drain the coolant.
4. Remove the drain bolt (A) from the right side of the engine block.
5. After the coolant has drained, apply liquid gasket, P/N 08718-0009, to the drain bolt threads, then reinstall the bolt with a new washer and tighten it securely.
6. Tighten the radiator drain plug securely.
7. Remove, drain, and reinstall the reservoir. Fill the tank to the MAX mark with Honda Long Life Antifreeze/Coolant Type 2 (P/N OL999-9001).
8. Remove the bleed cap (A) from the heater bypass tube.
9. Loosen the air bleed bolt (A) in the intake manifold, then pour Honda Long Life Antifreeze/Coolant Type 2 into the radiator to the bottom of the filler neck. Do not let coolant spill on any electrical parts or the paint. If any coolant spills, rinse it off immediately. NOTE: Always use Honda Long Life Antifreeze/Coolant Type 2 (P/N OL999-9001). Using a non-Honda coolant can result in corrosion, causing the cooling system to malfunction or fail. Honda Long Life Antifreeze/Coolant Type 2 is a mixture of 50% antifreeze and 50% water. Premixing is not required. Engine Coolant Refill Capacities (including reservoir capacity of 0.6 L (0.16 US gal)) After Coolant Change: 6.5 L (1.72 US gal) After Engine Overhaul: 7.6 L (2.01 US gal)
10. Tighten the air bleed bolt as soon as coolant starts to run out in a steady stream.
11. Reinstall the bleed cap on the heater bypass tube as soon as coolant starts to run out in a steady stream.
12. With the radiator cap off, start the engine and let it run until warmed up (radiator fan comes on at least twice). Then, if necessary, add more Honda Long Life Anti-freeze/Coolant Type 2 to bring the level back up to the bottom of the filler neck.
13. Put the radiator cap on tightly, then run the engine again and check for leaks.
14. Clean up any spilled engine coolant.

Scheme 9

1. Drain the engine coolant (see «COOLANT REPLACEMENT»(ref-221326-S23165940062006022400000) ).
2. Remove the lower radiator hose and the thermostat cover, then remove the thermostat.
3. Install the thermostat with a new rubber seal.
4. Install the thermostat cover and the lower radiator hose.
5. Refill the radiator with engine coolant, then bleed air from the cooling system (see step 8 ).
6. Clean up any spilled engine coolant.

Scheme 10

1. Drain the engine coolant (see «COOLANT REPLACEMENT»(ref-221326-S23165940062006022400000) ).
2. Remove the upper and lower radiator hoses.
3. 2000-2005 models: Disconnect the fan motor connectors and radiator fan switch connector.
4. 2006-2009 models: Disconnect the fan motor connectors and engine coolant temperature (ECT) sensor 2 connector.
5. Remove the radiator upper brackets and cushions, then pull up the radiator.
6. Remove both fan shroud assemblies and other parts from the radiator.
7. Install the radiator in the reverse order of removal. Make sure the upper and lower cushions are set securely.
8. Refill the radiator with engine coolant, then bleed the air from the cooling system (see step 8 ).
9. Clean up any spilled engine coolant.