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Sudden drop in fuel economy and a water leak?

Discussion in 'Gen 2 Prius Fuel Economy' started by adamortiz5, Apr 26, 2015.

  1. adamortiz5

    adamortiz5 Junior Member

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    I have a 2008 prius. Usually it gets me around 52-55mpg, I've had it since January. Since a couple of days ago its not giving me anything above 49. I know thats a normal number, but considering the fact that its usually quite a bit higher I'm wondering what the cause of the drop is. Also around the same time, when I pull out of my driveway I notice what appears to be a bit of water leakage. Its under the vehicle in the front center, and it only happens when I start the car for the day and pull out of my driveway (its on an incline).

    What could this mean?
     
  2. dolj

    dolj Senior Member

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    First of all, you can relax a bit. The difference between 49 and 52-55 MPG is marginal due the exponential nature of this measurement scale. I'm assuming that you record all your fill ups & milage and calculate your MPG rather than use the MFD consumption screen figure. If you don't calculate your MPG then that is a further area where error can come in.

    There are a few things to check that can account for this slight drop, e. g. tire pressures - are they at least what is placarded 35 PSI Front/33 PSI Rear? Some run their tires higher (including me) 39F/37R or 42F/40R. It just depends on how your tires are wearing at whichever pressure set. Have you recently changed your driving habits and now are doing more short trips? How's the weather?

    It could be engine/inverter coolant or it could just be condensation runoff from the A/C. You need to determine which, if it is just A/C runoff then there is no problem. There are plenty of threads here to search for leaking water pump and to also check that the inverter coolant pump is operating correctly.

    As I said, no real reason to be alarmed. Check out and see if any of the problems exist. If they do, get them fixed; if they don't, don't worry. Sometimes the Prius just does these things (variation in MPG) for no apparent reason. And, like I said it is not a significant difference.
     
    #2 dolj, Apr 26, 2015
    Last edited: Apr 26, 2015
  3. bisco

    bisco cookie crumbler

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    how many miles on her?
     
  4. adamortiz5

    adamortiz5 Junior Member

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    2008 Prius
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    She's got about 120k
     
  5. bisco

    bisco cookie crumbler

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    dolj has good advice, start there, and report back. have you done all the required maintenance to date? 120k is a big anniversary.