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2008 Tundra battery overheating & warng lights come on

Discussion in 'General Tundra Discussion' started by 2008 Tundra Mike, Jan 13, 2021.

  1. Jan 13, 2021 at 8:25 AM
    #1
    2008 Tundra Mike

    2008 Tundra Mike [OP] New Member

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    While driving yesterday all warning lights came on, check engine, vsc, slip control, abs, emergency brake at the same time the speedometer stopped. When I stopped everything went back to normal. As soon as I started to again all lights came back on. Went home and popped hood found battery really overheating. Hot or touch & could hear it boiling inside. Both battery & alternator replaced 3-4 years ago. Not sure if I have some kind of short or if alternator could be bad overcharging battery. Any advice would be greatly appreciated. Thanks
     
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  2. Jan 13, 2021 at 8:37 AM
    #2
    YardBird

    YardBird Native San Diegan

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    I hope someone here can help you with this issue. My first thought was a defective charging system ?
     
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  3. Jan 13, 2021 at 8:42 AM
    #3
    AZBoatHauler

    AZBoatHauler Desert Dweller

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    Assuming you have a serviceable battery, carefully pop the covers off and check the fluid level. If the top of the plates aren't covered with fluid add distilled water to get the top of the plates submerged. Then check your voltage with the truck off (should read between 12-12.6v). Assuming that's good, start the truck and check voltage at the battery again. It should be between 13.1-14.0v. If that checks out, I'd have the battery load tested or replaced.

    Did you use an OEM alternator when you replaced or aftermarket?
     
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  4. Jan 13, 2021 at 8:56 AM
    #4
    2008 Tundra Mike

    2008 Tundra Mike [OP] New Member

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    Thanks for the feedback, sealed battery but I checked the battery voltage it was right about 12.6. I'll still need to check when running. Not sure on the alternator being OEM or aftermarket. I will have to go back & check. It was replaced at a Goodyear shop about 3 years ago.
     
  5. Jan 13, 2021 at 9:00 AM
    #5
    AZBoatHauler

    AZBoatHauler Desert Dweller

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    What kind of battery? I assume it’s AGM since it’s sealed?
     
  6. Jan 13, 2021 at 9:01 AM
    #6
    TheBeast

    TheBeast The Beach

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    most likely aftermarket if not done at Toyota.
     
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  7. Jan 13, 2021 at 9:09 AM
    #7
    JohnLakeman

    JohnLakeman Burning Internet Daylight

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    Battery is being over-charged. Your charging system is running amuck. Hard to blame it on Goodyear if that work was done three years ago. Everything wears out eventually.
     
  8. Jan 13, 2021 at 12:43 PM
    #8
    crewmaxlmt

    crewmaxlmt New Member

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    Don't forget to check the charging voltage at different RPM's. Alternators have multiple sets of diodes to convert the AC electricity to DC throughout the operating range. Many of the alternator failures occur in the diodes.

    From my experience, when I replace the alternator I will replace the battery at the same time and vise versus.
     
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  9. Jan 13, 2021 at 3:37 PM
    #9
    2008 Tundra Mike

    2008 Tundra Mike [OP] New Member

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    Thanks great feedback, I'll be checking tomorrow. What's strange is 2008 tundra and had battery & alternator replaced in 2012 at toyota so that should / would have been OEM. Then alternator goes bad again in 2016. Had it replaced at tire shop could have been / probably aftermarket. So seems like I'm only averaging 4 years per alternator either oem or aftermarket. Does that seem normal ? Dont drive it alot only have 130,00 miles..
     
  10. Jan 13, 2021 at 7:51 PM
    #10
    crewmaxlmt

    crewmaxlmt New Member

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    That does not seem normal. I would check all of the electrical connections in the charging system.
     
  11. Jan 13, 2021 at 8:15 PM
    #11
    rons23

    rons23 Get The Led Out!!!

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    Negative, but KNOCK for me haha, I have my original alternator, and have replaced my battery once on my 08.
     
  12. Jan 13, 2021 at 8:39 PM
    #12
    blackdemon_tt

    blackdemon_tt New Member

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    Are you sure you're not overheating?? And the boiling might be coming from the radiator?? Engine is right by the battery so it may be normal the battery may feel hot to the touch... ECU may be trying to protect the engine...
     
  13. Jan 14, 2021 at 2:23 AM
    #13
    2008 Tundra Mike

    2008 Tundra Mike [OP] New Member

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    Thanks to all, good to have info on another "08" to compare against. Radiator looks good, not overheating, no fluid loss. Will be replacing the battery & alternator later tomorrow. Autopsy on alternator to follow. But today looks like I need to start digging into the electrical system a little deeper to see if anything looks out of norm.
     
  14. Jan 14, 2021 at 3:23 AM
    #14
    Haggis777

    Haggis777 Luke 12:15

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    I hope it's nothing expensive!
    From previous research, it could even be a bad/loose/corroded connection on the positive battery terminal.
    While you're replacing the battery and alternator, are you replacing the cables also?
     
  15. Jan 14, 2021 at 3:46 AM
    #15
    2008 Tundra Mike

    2008 Tundra Mike [OP] New Member

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    Terminals were pretty clean & tight when I pulled battery yesterday but I will take a better look today.
     
  16. Jan 14, 2021 at 9:36 AM
    #16
    2008 Tundra Mike

    2008 Tundra Mike [OP] New Member

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    Thanks to all for the feedback. Alternator was the problem overcharging battery. Was getting 20v from alternator back to battery. Crewmaxlmt owe you a beer. Spot on with the diodes. Went back and did my homework now I have a better understanding of what was going on. Bad diodes allowing enough ac voltage to bleed back thru electrical system causing the issues with all the warning lights. Voltage regulator in alternator not regulating voltage back to battery. That's why things got worst as I accelerated and went back to normal when I stopped. More rpms causing more voltage back thru system due to voltage regulator not working. Now i just need to check all wiring & connections to ensure no other issues. Got my GED in alternators this week. Thanks again to all for the feedback.
     
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  17. Jan 14, 2021 at 10:06 AM
    #17
    blackdemon_tt

    blackdemon_tt New Member

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    Dayum... glad you got it figured out, and thanks for the education....
     

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