Cooling System: Diagnosis Honda Pilot I

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 a 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

1. Lift height: above 10.0 mm (0.39 in.)
2. Starts opening: 169-176°F (76-80°C)
3. Fully open: 194°F (90°C)

Scheme 2

1. Remove the timing belt (see «TIMING BELT REMOVAL»(ref-173990-S32272518662005041500000) ).
2. Turn the water pump pulley counterclockwise. Check that it turns freely.
3. Check for signs of seal leakage. A small amount of "weeping" from the bleed hole (A) is normal.

Scheme 3

1. Drain the engine coolant (see «Coolant Replacement»(ref-173994-S39601808142005041500000) ).
2. Remove the timing belt (see «TIMING BELT REMOVAL»(ref-173990-S32272518662005041500000) ).
3. Remove the timing belt adjuster (see «TIMING BELT ADJUSTER REPLACEMENT»(ref-173990-S12972668962005041500000) ).
4. Remove the water pump (A) by removing five bolts.
5. Inspect and clean the O-ring groove and mating surface with the cylinder block.
6. Install the water pump with a new O-ring (B) in the reverse order of removal.
7. Clean up any spilled engine coolant.
8. Install the timing belt adjuster (see «TIMING BELT ADJUSTER REPLACEMENT»(ref-173990-S12972668962005041500000) ).
9. Install the timing belt (see «TIMING BELT INSTALLATION»(ref-173990-S11684977822005041500000) ).
10. Refill the radiator with engine coolant, and bleed air from the cooling system (see step 8 on «Coolant Replacement»(ref-173994-S39601808142005041500000) ).

Scheme 4

1. Look at the coolant level in the coolant reservoir. Make sure it is between the MAX mark (A) and MIN mark (B).
2. If the coolant level in the coolant reservoir is at or below the MIN mark, add coolant to bring it up to the MAX mark, and inspect the cooling system for leaks.

Scheme 5

Scheme 6

Scheme 7

Scheme 8

1. Turn the ignition switch ON (II). Set the climate control system to 90°F (32°C) or heater controls to full hot, then turn the ignition switch OFF. 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. Install a rubber hose (A) on the drain bolt (B) located at the rear of the cylinder block, then loosen the drain bolt.
5. When the coolant stops draining, tighten the drain bolt.
6. Tighten the radiator drain plug securely.
7. Remove, drain, and reinstall the coolant reservoir.
8. Pour Honda All Season Antifreeze/Coolant Type 2 into the radiator up to the base of the filler neck. NOTE: Always use Honda All Season Antifreeze/Coolant Type 2. Using a non-Honda coolant can result in corrosion, causing the cooling system to malfunction or fail. Honda All Season Antifreeze/Coolant Type 2 is a mixture of 50% antifreeze and 50% water. Premixing is not required. Engine Coolant Refill Capacity (including the reservoir capacity of 0.8 L (0.8 US qt): 7.0 L (7.4 US qt)
9. 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.
10. Turn off the engine. Check the level in the radiator, and add Honda All Season Antifreeze/Coolant Type 2, if needed.
11. Set the climate control or heater control panel to maximum cool. Start the engine. Hold the engine speed at 1,500 RPM for 5 minutes, then turn off the engine.
12. Check the level in the radiator, and add Honda All Season Antifreeze/Coolant Type 2, if needed.
13. Set the climate control or heater control panel to maximum heat. Start the engine. Hold the engine speed at 1,500 RPM for 5 minutes, then turn off the engine.
14. Check the level in the radiator, and add Honda All Season Antifreeze/Coolant Type 2, if needed.
15. Set the climate control or heater control panel to maximum cool. Start the engine. Hold the engine speed at 1,500 RPM for 3 minutes, then turn off the engine.
16. Check the level in the radiator, and add Honda All Season Antifreeze/Coolant Type 2, if needed.
17. Set the climate control or heater control panel to maximum heat. Start the engine. Hold the engine speed at 1,500 RPM for 3 minutes, then turn off the engine.
18. Check the level in the radiator, and add Honda All Season Antifreeze/Coolant Type 2, if needed.
19. Repeat steps 15 through 18 until the coolant level does not change in the radiator, then install the radiator cap loosely.
20. Set the climate control or heater control panel to maximum cool. Start the engine. Hold the engine speed at 2,500 RPM for 1 minute.
21. Set the climate control or heater control panel 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 2 or 3 minutes. Make sure the temperature is above the standard line of the graph shown. If the temperature is below the standard line, repeat steps 15 through 18 several more times. Then loosely install the radiator cap and recheck.
22. Make sure you do not hear the sound of water flowing near the rear heater unit. If you hear water flowing, repeat steps 15 through 18 several more times. Then loosely install the radiator cap and recheck.
23. Fill the reserve tank with Honda All Season Antifreeze/Coolant Type 2 up to the MAX mark on the tank, then add an extra 0.4 l (0.4 US qt) coolant.

Scheme 9

1. Make sure you have the anti-theft codes for the radio and navigation system, then write down the frequencies for the radio's preset buttons.
2. Disconnect the negative cable from the battery first, and then the positive cable.
3. Remove the battery.
4. Drain the engine coolant (see «Coolant Replacement»(ref-173994-S39601808142005041500000) ).
5. Remove the thermostat cover, then remove the thermostat.
6. Install the thermostat with new rubber seal.
7. Install the battery. Clean the battery posts and cable terminals with sandpaper, then assemble them and apply grease to prevent corrosion.
8. Refill the radiator with engine coolant, and bleed air from the cooling system (see step 8 on «Coolant Replacement»(ref-173994-S39601808142005041500000) ).
9. Clean up any spilled engine coolant.
10. Perform the powertrain control module (PCM) idle learn procedure (see «PCM IDLE LEARN PROCEDURE»(ref-173998-S03649363492005041500000) ), power window control unit reset procedure (see «RESETTING THE POWER WINDOW CONTROL UNIT»(ref-174055-S11132043692005042800000) ).
11. Enter the anti-theft codes for the radio and the navigation system, then enter the customer's radio station presets.
12. Set the clock.

Scheme 10

1. Make sure you have the anti-theft codes for the radio and navigation system, then write down the frequencies for the radio's preset buttons.
2. Disconnect the negative cable from the battery first, then the positive cable, and remove the battery.
3. Drain the engine coolant (see «Coolant Replacement»(ref-173994-S39601808142005041500000) ).
4. Remove the intake manifold cover and ignition coil cover (see step 6 on «ENGINE REMOVAL»(ref-173990-S30271460482005041500000) ).
5. Remove the vacuum hoses and breather pipe, then remove the intake air duct (see step 7 on «ENGINE REMOVAL»(ref-173990-S30271460482005041500000) ).
6. Remove the upper radiator hoses, lower radiator hose, heater hoses and water bypass hoses from the water passage, then remove the water passage.
7. Install the water passage in the reverse order of removal.
8. Install the battery. Clean the battery posts and cable terminals with sandpaper, then assemble them and apply grease to prevent corrosion.
9. Refill the radiator with engine coolant, and bleed air from the cooling system (see step 8 on «Coolant Replacement»(ref-173994-S39601808142005041500000) ).
10. Clean up any spilled engine coolant.
11. Perform the powertrain control module (PCM) idle learn procedure (see «PCM IDLE LEARN PROCEDURE»(ref-173998-S03649363492005041500000) ), power window control unit reset procedure (see «RESETTING THE POWER WINDOW CONTROL UNIT»(ref-174055-S11132043692005042800000) ).
12. Enter the anti-theft codes for the radio and the navigation system, then enter the customer's radio station presets.
13. Set the clock.