1. Attachments are working again! Check out this thread for more details and to report any other bugs.

2004 Prius Coolant Problem

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by Andrew Smillie, Nov 17, 2019.

  1. Andrew Smillie

    Andrew Smillie Junior Member

    Joined:
    Nov 17, 2019
    17
    4
    0
    Location:
    Dallas, TX
    Vehicle:
    2004 Prius
    Model:
    ----USA----
    I have a strange problem with my 2004 Prius. It has 230,000 miles on it and its been a stalwart ever since I bought it. For the last few years its been the kid car, taking my kids everywhere. Its on its second hybrid battery. Here is my problem:

    The coolant is leaking out somewhere and I can't figure out where. I got home from a weekend trip (not driving it) and there was coolant all over the driveway where it was parked. I took it to my mechanic and he couldn't find the leak so he gave it back to me. I can't find it either. I let the car idle one day for over 1 hour and it didn't leak at all. But its usually parked on the street and there are stains of what I think to be coolant puddles everywhere (and not small ones). There is always a tiny amount on the undercarriage but I can't see any leak.

    My mechanic thinks its leaking into the engine and that could be but I don't know why I am seeing coolant puddle stains everywhere where its parked and then there was the first one I saw before I took it to my mechanic.

    The leak seems to be coming from the passenger side. The puddles are on that side and there is a tiny bit of coolant on that side of the under carriage.

    Any thoughts?
     
    #1 Andrew Smillie, Nov 17, 2019
  2. Greenteapri

    Greenteapri Active Member

    Joined:
    Nov 19, 2018
    330
    387
    0
    Location:
    Cypress
    Vehicle:
    2013 Prius
    Model:
    Three
    Welcome!

    Chances are you have a coolant leak. From where, it's hard to tell from the pics.
     
    #2 Greenteapri, Nov 17, 2019
  3. Andrew Smillie

    Andrew Smillie Junior Member

    Joined:
    Nov 17, 2019
    17
    4
    0
    Location:
    Dallas, TX
    Vehicle:
    2004 Prius
    Model:
    ----USA----
    I am not sure what I would take pictures of. I can't find the leak.
     
    #3 Andrew Smillie, Nov 17, 2019
  4. Greenteapri

    Greenteapri Active Member

    Joined:
    Nov 19, 2018
    330
    387
    0
    Location:
    Cypress
    Vehicle:
    2013 Prius
    Model:
    Three


    Time to get your hands dirty or pony up some cash to have someone else look. I'm not sure what tools you have or your level of comfort is working on cars.
     
    #4 Greenteapri, Nov 18, 2019
  5. TMR-JWAP

    TMR-JWAP Senior Member

    Joined:
    Aug 12, 2016
    6,089
    5,806
    0
    Location:
    Columbia, SC
    Vehicle:
    2007 Prius
    Model:
    Touring
    The engine coolant pump is located on the passenger side, front bottom area. Belt driven. Use a flashlight to look at the inside of the pulley (where the pulley is hollow). This is probably the most common source of a coolant leak. The seal on the water pump wears out. Many times the first thing to be noticed will be pink crystals on the inside of the pulley (from seepage drying up). If the inside of the pulley is damp, I would guess you found your leak.

    Every time I work on a Gen 2 now, I use a flashlight to point out that pulley area to the owner. Just so they know what to look for. 50% of the time, there's some pink crystals there. Not enough to warrant a water pump change, but it warrants keeping an eye on. I just let them know they should eyeball it when they check their oil or open the hood for something. Once it becomes damp, then I consider it time to replace the pump.

    See the arrow in the below photo.

    waterpump.jpg
     
    #5 TMR-JWAP, Nov 18, 2019
    Last edited: Nov 18, 2019
    SFO and Skibob like this.
  6. PriusCamper

    PriusCamper Senior Member

    Joined:
    Mar 3, 2012
    10,899
    4,419
    0
    Location:
    Pacific Northwest, USA
    Vehicle:
    2007 Prius
    Model:
    Two
    Great opportunity to deep clean your engine compartment... You might find the leak while scrubbing every nook and cranny. And if you don't find the leak, the clean engine will make it easier to find once it gets worse.
     
    #6 PriusCamper, Nov 18, 2019
  7. Andrew Smillie

    Andrew Smillie Junior Member

    Joined:
    Nov 17, 2019
    17
    4
    0
    Location:
    Dallas, TX
    Vehicle:
    2004 Prius
    Model:
    ----USA----
    I took it in and the dealer found the thermostat housing cracked and the gasket shot. Not sure if it's "the" leak but it's a leak. Thanks all for the replies.
     
    #7 Andrew Smillie, Nov 18, 2019
    SFO, TMR-JWAP and Greenteapri like this.
  8. TMR-JWAP

    TMR-JWAP Senior Member

    Joined:
    Aug 12, 2016
    6,089
    5,806
    0
    Location:
    Columbia, SC
    Vehicle:
    2007 Prius
    Model:
    Touring
    That would do it. Hope that fixes it. It's good when it's an easy fix.
     
    #8 TMR-JWAP, Nov 18, 2019
(You must log in or sign up to post here.)