All of a sudden his battery light came on?

JENNYBOO513

MEMBER
2000 BMW 540I

My brother just called me from work and said when he was almost to work all of a sudden his battery light came on, his power steering went out, the temp gauge went all the way to high and when he pulled into the parking lot his car was in a cloud of smoke. Anybody have any suggestions as what could've happened? He never had any major issues with this car.

Sunday, February 22nd, 2009 AT 8:21 PM

1 Reply

SQM

MECHANIC
6,383 POSTS

Hello,

It sounds like the serpentine belt either came off the pulleys or broke off.
The serpentine belt controls all those functions that you mentioned is not working. It turns the power steering pump, the alternator and the water pump.
So without the belt the power steering pump will not pump and the steering will be hard to turn.
The alternator will not charge the battery and the battery light will come on.
The water pump will not circulate coolant thru the engine and the engine will overheat.

https://www.2carpros.com/articles/how-a-serpentine-belt-works
https://www.2carpros.com/articles/replace-serpentine-belt

I have attached diagrams for your reference.

Please let me know of any questions.
Thank you.

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