How to Replace the Inverter Coolant Pump

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by Patrick Wong, Jul 12, 2009.

  1. Patrick Wong

    Patrick Wong DIY Enthusiast

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    I've noticed that each summer a reasonable number of posters report inverter coolant pump failures. As a result I've recommended that owners consider replacing that pump no later than at 100K miles as a preventive measure.

    Taking my own advice, I decided to replace that pump on my 2004 with 81K miles since we are about to move to the very hot southern Arizona area. I'm not interested in having that pump fail in 110 degree F weather, resulting in a potential life-threatening emergency if we are stuck in the desert.

    I would rate the pump replacement as an intermediate level DIY project. It is not very easy because access to the pump is tight. You can see the pump if you open the hood and look behind the driver's side headlight assembly.

    What you will need:

    - G9020-47031 MSRP $116, Net $88 for weborders at Champion Toyota, Houston

    - One gallon of Toyota Super Long Life Coolant. You'll end up using 3 quarts or so.

    - 10 mm and 12 mm sockets, a good socket wrench and extensions. I found a U-joint was helpful as well as box wrenches in those sizes. You will need a 14 mm open end wrench and a 10 mm box wrench when opening the inverter coolant bleed valve. 24 mm (or 15/16") socket for the transaxle coolant drain plug.

    - Drain pan for old coolant

    The Toyota repair manual suggests removing both engine under covers to start. There is no reason to remove the RH under cover and the LH under cover doesn't provide much additional access. Hence I did the job working through the hood opening, except when draining the old coolant.

    Start by making the Prius IG-ON (not READY) and listen to the sound of the old inverter coolant pump, so that you have an idea of where you need to end up when you are done. You should see turbulence in the inverter coolant container and you should not hear air bubbling in the fluid. Then make the Prius IG-OFF.

    Drain the inverter/transaxle coolant by removing the 24 mm hex drain plug at the bottom of the transaxle. Do not confuse with the transaxle ATF fluid drain plug which requires a 10 mm hex key socket to remove. After the old coolant has been drained, tighten the drain plug to 29 ft.-lb.

    Remove the black plastic cover over the radiator. Then remove a nut and a bolt that secures a bracket for a water valve located near the pump. The reason that you have to remove the valve is because that bracket is mounted on the same stud, and located on top of the bracket for the inverter coolant pump. Then remove the bolt that secures the back end of the pump.

    Disconnect the wiring harness connector. You will need to squeeze the tab on the connector to release it. This is not easy to do.

    Remove the two hoses. Note which hose goes to which part of the pump. This is not too easy; I ended up using a flat-blade screwdriver to insert between the hoses and the pump inlet pipe and outlet pipe in order to break up the seal that had formed.

    Remove the pump from the car. There is barely enough room to lift the pump up between the radiator hose and the inverter.

    Note that the inverter cover has a couple of curves in the leading edge. The curve closest to the LH fender is where I positioned the top spout of the pump while removing it.

    Installation of the new pump is the reverse of the removal process. Tightening torque of the hardware is 62 in.-lb. The bolt at the rear of the pump, although needing a 12 mm socket, does not require greater torque since it is also holding down the plastic relay/fuse box.

    Fill the coolant reservoir with SLLC, using a plastic funnel to avoid spills. Keep filling until the fluid level stabilizes at the FULL mark. Make the car IG-ON for 20 seconds. As the fluid level drops, replenish to keep the fluid at FULL. Then make the car IG-OFF. Open the bleed valve until you see fluid appear, then close. Repeat the steps in this paragraph until the sound of the pump quiets down, you don't hear air in the system, you see turbulence in the inverter coolant reservoir, and the fluid level no longer drops below FULL.

    Take a test drive for a couple of blocks. Then check the fluid level when the car is IG-OFF. Top off as needed so the fluid level is at the FULL mark, make sure the bleed valve is tight, replace the radiator cover, and you are done.

    The old antifreeze is poisonous and very harmful to local fauna, pets etc. so please dispose of it responsibly.

    The first two photos show the inverter coolant pump outlet hose (forming a reverse S shape) in the middle, and the mounting hardware for the valve bracket immediately to the left and the right of that hose. You can see this is not easy to get to.

    The next photo shows the new pump and its part number.

    The next photo is blurry and underexposed unfortunately, but shows the location of the old pump. Note that it is in front of the main relay/fuse box (you can see the leading edge of the relay/fuse box where you depress the catch to release the cover) and behind the LH headlamp.

    The final photo shows the new and old pumps side by side.

    A curious note: I used my Fluke DMM to measure the resistance across the two terminals of the old pump which was still operational. The resistance value was around 1.5 M ohms. When I reversed the ohmmeter leads I got a negative value, so it appears that the pump has more to it than just a simple DC motor - looks like at least an inline diode and a capacitor are involved, who knows what else. I did not measure the resistance of the new pump.
     

    Attached Files:

  2. CharlesJ

    CharlesJ Member

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    Great, thanks.:D

    How long did this take you and what was the savings, if you know.
     
  3. Patrick Wong

    Patrick Wong DIY Enthusiast

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    Hi Charles,

    I spent around four hours, but this is because I had removed the under covers, spent time looking around for the pump, replaced broken plastic fasteners around the car, tried to figure out the best way to remove the pump, struggled with the hoses trying not to damage them, etc. Galaxee will probably say that her DH can do the job in 20 minutes... :cool:

    My guess is that a Toyota dealer's service dept will probably charge around 2 hours of labor and charge MSRP or more for the part. So, your bill might be ~$300 or more, depending upon the labor rate in your locale.
     
  4. Flying White Dutchman

    Flying White Dutchman Senior Member

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    great info thx
    expensif Inverter Coolant Pump 88.....
     
  5. saechaka

    saechaka Member

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    Quick question. I'm at 164,000miles and at the point where I need to change the psd fluid. I was wondering if it might be better to have the inverter pump replaced rather than just changing the psd fluid because they change the psd fluid when they replace the inverter pump anyways. Any thoughts? Thanks
     
  6. Patrick Wong

    Patrick Wong DIY Enthusiast

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    Please note that there are two separate fluids in the picture:

    1. Toyota SLLC which cools the inverter and transaxle
    2. Toyota ATF WS which lubricates the transaxle

    As you say "psd fluid", I assume you mean #2 above. If you have the transaxle ATF changed, this has nothing to do with the inverter coolant loop and therefore the coolant will remain unchanged. If you have the inverter pump replaced, then the SLLC will automatically be replaced but again, this has nothing to do with the ATF.

    At your car's odometer reading, the coolant should have been changed at least twice by now: once at 100K miles and the second time at 150K miles. The transaxle ATF should have been replaced at 60K mile intervals or shorter to promote longevity of that component.
     
  7. jayman

    jayman Senior Member

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    Just curious, would the bleeding process have been easier if you had run a small tube from the bleeder screw, directly into the reservoir?

    So instead of opening and closing the screw, you could have left it open until the bubbles settled down

    I've done that trick to bench-bleed master cylinders, which are probably not related to the inverter coolant system in complexity
     
  8. morrisnk

    morrisnk New Member

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    My inverter coolant pump just went out the other day (89,000 mi) and the dealer's service center is telling me that all their pumps are on back order at Toyota's national parts distribution till July 23rd.

    This is such a timely post, I'm thinking about getting my car back and doing it myself and save some time (I can get a 3rd party part faster) and money (they quoted me $375).

    -Nathan
     
  9. usbseawolf2000

    usbseawolf2000 HSD PhD

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    Thanks!

    I just passed 100k miles. I made an appointment to change the coolant this Thursday. I may decide to do it myself and change the pump as well.

    What is the shelf life for SLLC? I have 4 bottles that are 3-4 years old. Should I use them? :D
     
  10. ETP

    ETP 2019Prius(Limited),Highlander HYB Plat,B52-D,G,F,H

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    Would this be covered under the Toyota extended warranty?
    I am about to leap on this plan.
     
  11. Patrick Wong

    Patrick Wong DIY Enthusiast

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    Hi Jay, Actually the repair manual does recommend running a clear vinyl tube from the bleed screw into the reservoir, just as you suggested. However I did not bother with that step and each time I opened the bleed screw, fluid immediately appeared. It really took only three or four iterations to fill up the system and eliminate the air trapped within.
    Hi Nathan,Where would you get a third party inverter coolant pump, and what is the price for that?
    Yes, I do not believe that antifreeze has a particular shelf life. I would use the contents of the 4 year old bottles without concern.
    Yes, however a preventive replacement as I advocated would not be covered.
     
  12. saechaka

    saechaka Member

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    Thanks it seems I've got some things that need attention. I've last changed my coolant at 100k miles and transaxle ATF at 60k miles. Could that be why my car burns a little over a quart of oil every 5k miles?
     
  13. jayman

    jayman Senior Member

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    I checked the shop manual, yep it does. Seems not as messy. I hope you were careful to mop up any spilled coolant, pets find coolant sweet tasting and will drink it
     
  14. jayman

    jayman Senior Member

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    No, it's probably because a lower quality oil allowed heavy ring land deposits on the pistons. As a result, the oil control ring is floating and allowing oil consumption.

    If you sample your used oil, you will probably find evidence of increased blowby as well. There are oil additive products that claim to safely remove these sort of deposits. I have never used them, and have no idea if they really work
     
  15. saechaka

    saechaka Member

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    Well I was using Synthetic Mobil 1 5-20w for the first 60k miles at and switched over to Motorcraft w/10k mile intervals until I hit about 150k then I switched over to 5k oil change with Motorcraft. It seems like now is a good time to do oil analysis.
     
  16. usbseawolf2000

    usbseawolf2000 HSD PhD

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    I just checked the TSB EG001-07 and my VIN number is less than the list for 2006. I have never gotten a letter about this and my car is now out of 60k warranty. Damn it!

    Patrick, did you confirm your old pump part number as G9020-47030? Luscious Garage said the old part has black bracket. Your picture indicates silver bracket for the old replaced pump.

    When I replace my pump I will try to see if there is a part number for it. If it is the improved design (G9020-47031), I would feel like a waste of effort. May be not.. it may last another 150-200k miles.
     
  17. Patrick Wong

    Patrick Wong DIY Enthusiast

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    Yes, you would not have received a notification because the bulletin cited is an TSB, not an SSC (aka recall.)

    I don't know what the old pump part number is. I did not notice part numbering on either the new or the original pump. You are right that the two pumps look quite alike except for dirt on the original.

    Have you had a chance to take a look at the pump in your car to see whether the metal bracket is plated silver or painted black?
     
  18. usbseawolf2000

    usbseawolf2000 HSD PhD

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    I looked with the flashlight to see where it was but at that time I wasn't looking for the plate. I will report back after I check it.
     
  19. usbseawolf2000

    usbseawolf2000 HSD PhD

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    I checked it out yesterday. The mounting plate seems silver plated. It has corrosion on it and a bit hard to tell.
     
  20. vertex

    vertex Active Member

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    What is the deal with using the Toyota antifreeze? The service manual specifically says any high quality ethylene glycol antifreeze is OK.
     
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