Q: Serpentine belt broke

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My Serpentine belt broke while driving and battery light came on. Drove 15 miles before i arrived home and shut car off. Tried to restart but it the battery was dead. Woke up in the morning car started just fine. I let the car run without driving and After about 7 mins car died again not completely. I shut it off and tried to restart and it was like the battery was dead. Its the orginal serpentine belt from mfg. So its 120,000 miles in. All pulleys seemed to be fine prior as i lifted my hood and never hear squeaks or see signs of the belt tensioners needing to be replaced. Should i still replace all belt tensioners? Is this a Sign of a faulty alternator?.

My car has 120000 miles.
My car has an automatic transmission.

Hello. Yes, the idler pulley and tensioner should be replaced with the serpentine belt. The bearing in the idler pulley wears out over the miles and the tensioner weakens with use as well.

This is not a sign of a faulty alternator. The battery is capable of running engine electronics for a short distance and you were probably most fortunate to get home before that occurred. I am very surprised you did not have an overheating event, as the serpentine belt also drives the water pump. Driving any distance (let’s say a mile) usually causes severe overheating.

If you would like to have this checked, a certified professional from YourMechanic can come to your car’s location to replace the serpentine belt and any other repair that is needed.

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