Home ReviewsRefund
Home/Honda/Pilot/Honda Pilot II (2008-2011)/Repair manual/Cooling System (Mechanical)/Cooling System: Diagnosis
Contents Wiring diagrams Section: Cooling System (Mechanical) All sections

Cooling System: Diagnosis Honda Pilot II

Cooling System (Mechanical) 13 illustrations ~1575 words

Thermostat Test

Replace the thermostat if it is stuck in the open position at room temperature.

To test a closed thermostat

Scheme 5

Scheme 5: Thermostat Test
Scheme 5: Thermostat Test
  1. Suspend the thermostat (A) in a container of water. Do not let the thermostat and the thermometer (B) touch the bottom of the hot container.
  2. Heat the water, and check the temperature with a thermometer. Check the temperature when the thermostat first opens, then check the temperature again when the thermostat is fully open.
  3. Measure the lift height of the thermostat when it is fully open. If the thermostat is not within the specification, replace it. Standard Thermostat Lift Height: Above 10.0 mm (0.394 in.) Starts Opening: 169-176°F (76-80°C) Fully Open: 194°F (90°C)

Scheme 6

Scheme 6: Water Pump Inspection
Scheme 6: Water Pump Inspection
  1. Remove the timing belt (see «TIMING BELT REMOVAL»(ref-333551-S34987126892009072100000) ).
  2. Turn the water pump pulley counterclockwise, and check that it turns freely. If it does not turn freely, replace the water pump (see «Water Pump Replacement»(ref-333555-S24287451402009072100000) ). NOTE: When you check the water pump, you may see a small amount of "weeping" from the bleed holes (A). This is normal.
  3. Install the timing belt (see «TIMING BELT INSTALLATION»(ref-333551-S12213281632009072100000) ).

Scheme 7

Scheme 7: Water Pump Replacement
Scheme 7: Water Pump Replacement
  1. Drain the engine coolant (see «COOLANT CHECK»(ref-333555-S24547779662009072100000) ).
  2. Remove the timing belt (see «TIMING BELT REMOVAL»(ref-333551-S34987126892009072100000) ).
  3. Remove the timing belt adjuster (see «TIMING BELT ADJUSTER REPLACEMENT»(ref-333551-S40840024512009072100000) ).
  4. Remove the five bolts securing the water pump (A), then remove the water pump.
  5. Inspect and clean the O-ring groove and the mating surface of the engine block.
  6. Install the water pump using a new O-ring (B).
  7. Clean up any spilled engine coolant.
  8. Install the timing belt adjuster (see «TIMING BELT ADJUSTER REPLACEMENT»(ref-333551-S40840024512009072100000) ).
  9. Install the timing belt (see «TIMING BELT INSTALLATION»(ref-333551-S12213281632009072100000) ).
  10. Refill the radiator with engine coolant, and bleed the air from the cooling system (see step 11 on «COOLANT REPLACEMENT»(ref-333555-S19429433502009072100000) ).

Scheme 8

Scheme 8: Coolant Check
Scheme 8: Coolant Check
  1. Check the coolant level in the coolant reservoir. Make sure it is between the MAX mark (A) and the MIN mark (B).
  2. If the coolant level in the coolant reservoir is at or below the MIN mark, add coolant to bring it between the MIN and MAX marks, then inspect the cooling system for leaks.
  3. Check the coolant level in the radiator, and add Honda Long Life Anitfreeze/Coolant Type 2 into the radiator up to the base of the filler neck, if needed. NOTE: Always use Honda Long Life Antifreeze/Coolant Type 2. Using a non-Honda coolant can result in corrosion, causing the cooling system to malfunction or fail. Honda Long Life Anitfreze/Coolant Type 2 is a mixture of 50% anitfreeze and 50% water. Do not add water.

Scheme 9

Scheme 9: Coolant Replacement
Scheme 9: Coolant Replacement

Scheme 10

Scheme 10
Scheme 10

Scheme 11

Scheme 11
Scheme 11

Scheme 12

Scheme 12
Scheme 12

Scheme 13

Scheme 13
Scheme 13
  1. Remove the radiator cap.
  2. Open the splash shield cover (A).
  3. Loosen the drain plug (B) and drain the coolant.
  4. Remove the rocker arm oil pressure sensor cover (see step 8 on «CRANKSHAFT AND PISTON REMOVAL»(ref-333552-S30813783042009072100000) ).
  5. Install a rubber hose (A) on the drain bolt (B) located at the rear of the engine block, then loosen the drain bolt.
  6. When the coolant stops draining, tighten the drain bolt. Remove the rubber hose, then install the rocker arm oil pressure sensor cover (see step 39 on «CRANKSHAFT AND PISTON INSTALLATION»(ref-333552-S17557117932009072100000) ).
  7. Tighten the radiator drain plug securely.
  8. Close the splash shield cover.
  9. Remove, drain, and reinstall the coolant reservoir.
  10. Fill the coolant reservoir to the MAX mark (A) with Honda Long Life Antifreeze/Coolant Type 2.
  11. Pour Honda Long Life Antifreeze/Coolant Type 2 into the radiator up to the base of the filler neck. NOTE: Always use Honda Long Life Antifreeze/Coolant Type 2. 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. Do not add water. Engine Coolant Capacities (Including the coolant reservoir capacity of 0.75 L (0.198 US gal)): At Coolant Change: 7.5 L (1.98 US gal) After Engine Overhaul: 9.4 L (2.48 US gal)
  12. Start the engine. Hold the engine speed at 1,500 RPM until it warms up (the radiator fan comes on at least twice). Make sure the thermostat is open.
  13. Turn off the engine. Check the level in the radiator, and add Honda Long Life Antifreeze/Coolant Type 2, if needed.
  14. Set the climate control or HVAC control unit to maximum cool. Start the engine. Hold the engine speed at 1,500 RPM for 5 minutes, then turn off the engine.
  15. Check the level in the radiator, and add Honda Long Life Antifreeze/Coolant Type 2, if needed.
  16. Set the climate control or HVAC control unit to maximum heat. Start the engine. Hold the engine speed at 1,500 RPM for 5 minutes, then turn off the engine.
  17. Check the level in the radiator, and add Honda Long Life Antifreeze/Coolant Type 2, if needed.
  18. Set the climate control or HVAC control unit to maximum cool. Start the engine. Hold the engine speed at 1,500 RPM for 3 minutes, then turn off the engine.
  19. Check the level in the radiator, and add Honda Long Life Antifreeze/Coolant Type 2, if needed.
  20. Set the climate control or HVAC control unit to maximum heat. Start the engine. Hold the engine speed at 1,500 RPM for 3 minutes, then turn off the engine.
  21. Check the level in the radiator, and add Honda Long Life Antifreeze/Coolant Type 2, if needed.
  22. Repeat steps 18 through 21 until the coolant level does not change in the radiator, then install the radiator cap loosely.
  23. Set the climate control or HVAC control unit to maximum cool. Start the engine. Hold the engine speed at 2,500 RPM for 1 minute.
  24. Set the climate control or HVAC control unit to maximum heat, and select high speed heat mode on the rear control panel. Measure the temperature of the air from the rear floor vent for 3 minutes. Make sure the temperature is above the standard line of the graph as shown. If the temperature is below the standard line, repeat steps 18 through 21 several more times. Then loosely install the radiator cap and recheck.
  25. With the engine idling, make sure you do not hear the sound of water flowing near the rear heater unit. If you hear water flowing, repeat steps 18 through 21 several more times.
  26. Install the radiator cap securely.
  27. Fill the coolant reservoir with Honda Long Life Antifreeze/Coolant Type 2 up to the MAX mark on the coolant reservoir, then add an extra 0.4 L (0.11 US gal) of coolant.
  28. If the maintenance minder required engine coolant replacement, reset the maintenance minder (see «MAINTENANCE MAIN ITEMS»(ref-333543-S23745298982009072100000) ). If the maintenance minder did not require engine coolant replacement, go to step 29.
  29. Turn the ignition switch to LOOK (0).
  30. Connect the Honda Diagnostic System (HDS) to the data link connector (DLC) (see step 2 on (see «GENERAL TROUBLESHOOTING INFORMATION»(ref-333557-S00859668402009072100000) ).
  31. Turn the ignition switch to ON (II).
  32. Make sure the HDS communicates with the vehicle and the powertrain control module (PCM). If it does not communicate, troubleshoot the DLC circuit (see «DLC CIRCUIT TROUBLESHOOTING»(ref-333558-S02093989162009072100000) ).
  33. Select GAUGES in the BODY ELECTRICAL with the HDS.
  34. Select ADJUSTMENT in the GAUGES with the HDS.
  35. Select MAINTENANCE INFORMATION in the ADJUSTMENT with the HDS.
  36. Select RESET in the MAINTENANCE INFORMATION with the HDS.
  37. Select MAINTENANCE SUB ITEM 5 RESET with the HDS.
  38. Clean up any spilled engine coolant.
  39. Inspect for engine coolant leaks.

Scheme 14

Scheme 14: Thermostat Replacement
Scheme 14: Thermostat Replacement
  1. Drain the engine coolant (see «COOLANT CHECK»(ref-333555-S24547779662009072100000) ).
  2. Remove the air intake duct (see step 1 on «FRONT BULKHEAD COVER REPLACEMENT»(ref-333593-S12466888562009072100000) ).
  3. Do the battery removal procedure (see «BATTERY REMOVAL AND INSTALLATION»(ref-333608-S42868124562009072100000) ).
  4. Remove the battery base (see step 9 on «ENGINE REMOVAL»(ref-333550-S08423022402009072100000) ).
  5. Remove the thermostat cover, then remove the thermostat.
  6. Install the new thermostat (with the pin up) using a new rubber seal, then install the thermostat cover.
  7. Install the battery base (see step 56 on «ENGINE INSTALLATION»(ref-333550-S05584759992009072100000) ).
  8. Do the battery installation procedure (see «BATTERY REMOVAL AND INSTALLATION»(ref-333608-S42868124562009072100000) ).
  9. Install the air intake duct (see step 1 on «FRONT BULKHEAD COVER REPLACEMENT»(ref-333593-S12466888562009072100000) ).
  10. Refill the radiator with engine coolant, and bleed the air from the cooling system with the heater valve open (see step 11 on «COOLANT REPLACEMENT»(ref-333555-S19429433502009072100000) ).
  11. Clean up any spilled engine coolant.
  12. Inspect for engine coolant leaks.

Scheme 15

Scheme 15: Water Passage Replacement
Scheme 15: Water Passage Replacement

Scheme 16

Scheme 16
Scheme 16

Scheme 17

Scheme 17
Scheme 17
  1. Drain the engine coolant (see «COOLANT CHECK»(ref-333555-S24547779662009072100000) ).
  2. Remove the air intake duct (see step 1 on «FRONT BULKHEAD COVER REPLACEMENT»(ref-333593-S12466888562009072100000) ).
  3. Do the battery removal procedure (see «BATTERY REMOVAL AND INSTALLATION»(ref-333608-S42868124562009072100000) ).
  4. Remove the battery base (see step 9 on «ENGINE REMOVAL»(ref-333550-S08423022402009072100000) ).
  5. Remove the intake air duct (see step 7 on «ENGINE REMOVAL»(ref-333550-S08423022402009072100000) ).
  6. Disconnect the upper radiator hose (A), the lower radiator hose (B), the engine coolant temperature (ECT) sensor 1 connector (C), and the exhaust gas recirculation (EGR) valve connector (D).
  7. Disconnect the water bypass hoses (A) and the heater hose (B).
  8. Remove the EGR pipe (see «EGR VALVE REPLACEMENT»(ref-333565-S28763655732009072100000) ).
  9. Remove the water passage and the related parts.
  10. Install the water passage and the related parts.
  11. Install the intake air duct (see step 58 on «ENGINE INSTALLATION»(ref-333550-S05584759992009072100000) ).
  12. Install the battery base (see step 56 on «ENGINE INSTALLATION»(ref-333550-S05584759992009072100000) ).
  13. Do the battery installation procedure (see «BATTERY REMOVAL AND INSTALLATION»(ref-333608-S42868124562009072100000) ).
  14. Install the air intake duct (see step 1 on «FRONT BULKHEAD COVER REPLACEMENT»(ref-333593-S12466888562009072100000) ).
  15. Refill the radiator with engine coolant, and bleed the air from the cooling system (see step 11 on «COOLANT REPLACEMENT»(ref-333555-S19429433502009072100000) ).
  16. Clean up any spilled engine coolant.
  17. Inspect for engine coolant leaks.

More articles — Cooling System