coolant pump still failed early with loose drive belt

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by epoch_time, Mar 28, 2014.

  1. epoch_time

    epoch_time Active Member

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    I loosened coolant pump belt when my gen II prius had only 200 miles on it.
    I retensioned it approximately 70% less. Where I could turn water pump pully by hand breaking traction with drive belt using all my strength.

    The ice coolant pump just started to leak at the weep hole at only 63000 miles and 5 years old.
    I was sure the reduced tension would make coolant pump last much longer.

    After retentioning it (brand new at 200 miles) I could deflect belt about one inch as opposed to not able to deflect belt at all!

    Checking belt traction against cooling pump pully (today 63000 miles later) crank-shaft rotates before water pump pulley looses any grip against belt.

    No loss in tension or pulley/belt traction after 63000 miles.

    Not happy with oem coolant pump quality!

    Has any one figured out yet if a newer electric prius ice coolant pump can be bolted to a gen II block?
     
    #1 epoch_time, Mar 28, 2014
  2. JC91006

    JC91006 Senior Member

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    If you can tighten and loosen the belt, you should be mechanically inclined to replace the water pump yourself. The price of the part and a new belt will be under $100. Is that reasonable for 63000 miles? Why re-engineer your car for only $100 out of pocket to repair what you have now?
     
    #2 JC91006, Mar 28, 2014
  3. epoch_time

    epoch_time Active Member

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    Yes I can change the pump and bleed air out of system thanks to the resourcefull prius-chatters.
    But hope that a no tension electric pump would be more efficiant and longer lasting.

    As long as I must get my hands dirty . I might as well go for an inproved design.

    All tension belts consume power and energy. I would get at least 2 more miles per gallon with electric coolant pump.
     
    #3 epoch_time, Mar 28, 2014
  4. uart

    uart Senior Member

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    My understanding is that reduced tension should (in theory) make the bearings last longer, but I don't know if that necessarily translates into longer seal life.
     
    #4 uart, Mar 28, 2014
  5. jadziasman

    jadziasman Prius owner emeritus

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    The Gen 3 and Gen 2 engines are not similar enough for you to use a Gen 3 electric water pump on a Gen 2 block.
     
    #5 jadziasman, Mar 28, 2014
  6. Patrick Wong

    Patrick Wong DIY Enthusiast

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    Considering that the OP lives in Las Vegas which has very hot summer weather, may I suggest that it is more appropriate to make sure the engine coolant pump is properly installed with correct tightness of the serpentine drive belt, rather than tolerating the belt being loose and running the risk of the belt slipping off when the summer temps are 110 degrees F. A loose belt will also have its surface glaze up faster (which results in slipping) as compared to a correctly tensioned belt.

    I personally have no complaints about the longevity of the original equipment engine coolant pump, I replaced the original on the 2004 last fall (after 160K miles or so) just because I had a replacement pump available, but the original was still in good condition with only a tiny weeping from the bearing, not sufficient to leave any deposits on the AC compressor housing.

    The G3 Prius electric pump requires control via the engine ECU to determine how fast to run the pump motor, while the ECU also has a sensor to detect pump failure. This would not be a very easy retrofit to the G2 engine since there would be both mechanical as well as electrical fit issues.

    I do not think it would improve vehicle reliability to install an electric coolant pump without an independent means to detect pump failure (think about the G2 inverter coolant pump, if you require an example illustrating my assertion.)
     
    #6 Patrick Wong, Mar 28, 2014
  7. epoch_time

    epoch_time Active Member

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    Anybody know of a toyota radiator cap that holds less pressure than the oem. And will fit genII prius?
    The oem radiator cap is rated at 88kpa about 12.8 psi . I would love a radiator cap with half that rating.

    Less coolant pressure less coolant loss.
    Apparently 50/50 antifreeze/water boils at 223 fahrenhite at sea level.
    And every pound of pressure adds 3.5 degrees to the boiling point.
    At 10000 ft above sea level 50/50 mix boils around 200 fahrenhite.

    I will keep orignal 12.8psi radiator cap for high altitude summer driving.
     
    #7 epoch_time, Mar 28, 2014
  8. MarcSmith

    MarcSmith Active Member

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    nice thing about the belt operated pump... even when it leaks, it is still pumping.

    when the electric pump fails. Chances are you'd never know until the idiot light comes on...
     
    #8 MarcSmith, Mar 28, 2014
  9. JC91006

    JC91006 Senior Member

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    The Toyota engineers have engineered the car with the correct parts. Why mess with what has been engineered by car builders? I assume you are still trying to resolve the leaking pump issue, but that once again is $100 out of pocket expense after 63000 miles. I must not understand why you feel it's necessary to do what you're doing. I can understand you toying with the car if you are constantly replacing a part that's $1000. But that's not the case here
     
    #8 JC91006, Mar 28, 2014
  10. epoch_time

    epoch_time Active Member

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    I'm not trusting toyota of america replacement parts.
    I see people changing wheel bearings purchased from toyota dealers and only getting 20000 miles before failing.
    I purchased a new 12 volt prius battery from dealer three years ago its toast and it had and easy life.
    The new dealer (spent battery) is five pounds lighter than the orignal battery ( I still have both batteries).

    The orignal goodyear tires are only half gone at 63k miles. No one gets half that from american made goodyear integras.
    The orignal oil filter from toyota japan is far superior than the thailand oil filter sold by toyota dealers (toyota thailand oil filter is still best available prius oil filter in usa).

    I purchased an extra coolant pump belt from the dealer it is very cheep looking . string cord material unevenly exposed around its edges .It will only be installed if the orignal should totally fail. Orignal belt looks perfect at 63 k miles.
    Save your orignal belt!



    I believe the engineers did a remarkable job with parts lasting just beyond warrenty periods!

    I've never had a factory water pump fail before 8 years or 90k miles ( properly tensioned).
    100 dollars every 60k miles would marginally acceptable. I'm certain a dealer pump will not last near that long!
    Why would toyota engineers tension the coolant pump 70% to tight in the first place if they are so perfect.
    After removing 70% of the belt tension with only 200 miles on my prius and 63k miles later. I can turn the water pump pulley with my hand and the belt after 63 k grips enough to turn the entire engine over!

    Get my drift.

    I have never let anyone work on my vehicles but myself. Ive got 42 years experience now and I don't
    Like getting my hands dirty. But I am the only one who does the job right. And have driven all my vehicles in excess of 200 k miles. And have never had to replace wheel bearings, only have had to change water pumps, master brake cylinders, alternator and starter brushes, heator cores, batterys, etc.
     
    #9 epoch_time, Mar 28, 2014
  11. tanglefoot

    tanglefoot Whee!

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    I was kind of wondering if less belt tension might keep the pump leak-free longer. Thanks for the account.

    The pump in mine was leaking at 44k miles, 7 years. Hopefully the replacement lasts longer. It's not too bad of a DIY job though. Can't complain, considering how easy this car is to own, overall.
     
    #10 tanglefoot, Mar 28, 2014
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