replaced water pump and belt and now runs hot

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by karinfrench, Jun 30, 2011.

  1. karinfrench

    karinfrench New Member

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    :confused:Toyota dealer said computer indicated the water pump and belt needed replacing. We decided to do the replacement ourself. Now the light comes on which indicates car is running hot. We did replace the coolant. The 2005 Toyota Prius never ran hot before the replacement, What did we do wrong?
     
    #1 karinfrench, Jun 30, 2011
  2. kammssss

    kammssss Member

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    How much coolant were you able to put back in? I had the same problem with my 05. I had to keep on adding coolant, about 1 gallon, until it was truly full. You can tell when it is full when the engine doesn't have to siphon any from the reservoir.
     
    #2 kammssss, Jul 1, 2011
  3. andyprius

    andyprius Senior Member

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    You have to bleed the radiator system, as you face the car, to the right side and on top, there is a allen wrench that you have to open while filling. Don't try running car until you think that the radiator and overflow tank is full. You can see air bubbles coming out of the radiator. Be careful it can get so hot, the engine can steam. I speak from personal experience. Initially only run it for one minute!:eek:
     
    #3 andyprius, Jul 1, 2011
  4. Patrick Wong

    Patrick Wong DIY Enthusiast

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    1. The engine ECU would have no reason to indicate that the engine coolant pump or the serpentine belt needs to be replaced. However you can use visual means to determine that either is defective: if you see coolant leakage at the pump pulley, and cracking of the belt's interior when it is removed, or a shiny exterior which shows the belt is glazed. Also, when the belt is removed, you can rotate the pump by hand to assess the condition of the pump bearing.

    2. Clearly, there is some air remaining in the engine cylinder head coolant passages which results in the engine overheating. If you run the cabin air heater you will probably hear air in the system. When changing engine coolant, it is necessary to measure the amount of coolant that you drained. Until you have added back the same amount of new coolant you cannot be satisfied that the job is complete.

    3. If you opened up all three drains (engine block, radiator, and coolant heat recovery system canister) then you will need to refill with ~6.5 US quarts of new Toyota Super Long Life coolant. Capacity of the engine coolant system is ~9 US quarts but some coolant is retained in the cabin heater core and plumbing.

    4. See my posts #22 and #42 here for my suggestions about how to do this job correctly:
    http://priuschat.com/forums/gen-ii-...shooting/30813-changing-engine-coolant-5.html
     
    #4 Patrick Wong, Jul 1, 2011
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