Wheel bearing effect on gas mileage?

Discussion in 'Newbie Forum' started by 80sguy, Jan 22, 2023.

  1. 80sguy

    80sguy New Member

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    Hi folks, thanks for all the helpful information. Newer member but I learned a lot. I just replaced my '08 Prius with a second OE Prius, first one dueled with a deer and lost.
    We actually have three Priuses in the family and most get very similar gas mileage depending on who's driving and conditions, 43 to 49. The new one I just got is going to need a wheel bearing in the not too distant to near future. Could this have a significant effect on gas mileage? This gets 36 or 37 miles per gallon. It has 225 k on the odometer which is 35,000 less thin my previous '08. Put in a new 12 volt battery because it seemed like the ICE ran more then it should compare to my other ones. Plus I think that battery might have had a bad cell according to my charger. Like I said, the wheel bearing is not terrible at this point and while it's on my radar, I'm wondering whether I should keep this Prius and move on to something else. Since I live in deer country and my kids drive these cars a lot, As long as I'm only going to get mid to high 30s, there are other options that are bigger and safer. Please let me know what you think. By the way, recent oil change of 5W30 synthetic.
     
  2. PriusCamper

    PriusCamper Senior Member

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    Probably not... In some cases it could hurt MPG, in other cases it won't... Conditions might change too... Try periodically jacking up that wheel and testing how it spins. If it ever gets really hard to spin that's when MPG will go down.
     
  3. Todd Bonzalez

    Todd Bonzalez Member

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    If you jack up the corner with the "bad" bearing and turn the wheel by hand, do you feel more resistance than say the wheel on the opposite side?

    Last bad wheel bearing I had was so bad, the wheel nuts were too hot to touch when I took the wheel off. That kind of friction will probably affect your fuel economy:LOL:

    Your tires will probably have a bigger effect tbh
     
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  4. BiomedO1

    BiomedO1 Active Member

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    A bad bearing would have to be howling very loudly to affect your mileage that badly.

    Check for brake drag; lube those caliber slide pins and clean the battery cooling fan system. I'm pretty sure your low mileage has more to do with borderline modules in your traction battery pack. If you got a good OBDII; check the fuel mapping. Intermittent/borderline, MAF, O2 sensor, and temperature sensors can cause the car to run rich and not trip the CEL - that's why you need to look at the fuel injector mapping.

    Hope this helps.
     
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  5. vvillovv

    vvillovv Senior Member

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    @80sguy since you mentioned a bad cell, it sounds to me like you were referring to the 12 volt and it's charger. The other prius battery can also effect the mileage. I like to recommend DrPrius app for almost everything regarding the Prius Traction Pack. Since you have 3 Prii you already have a great test bed for using the app to compare your cars.
     
  6. 80sguy

    80sguy New Member

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    Thanks that's a good place to start. I don't think there's brake drag...no heat and no smell, so if present it would have to be very very slight.
    Where is the battery cooling fan to check?
     
  7. 80sguy

    80sguy New Member

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  8. 80sguy

    80sguy New Member

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    Thank you, yes it was bad cell in 12v...figured it was causing ICE to run more for alternator to charge it? IDK, just seemed logical.
    Isn't there some adapter or something to go with the Dr Prius?
     
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