Dead alternator? Car dies at traffic light.

[pierreb]

I did search but I'm not 100% sure on symptoms and car won't get looked at by a professional until tomorrow at the earliest.

Driving to the parts store (irony overload) for brake pads for another car. Hearing a whine that goes up and down with rpm. Last traffic light before parts store and car starts stumbling. Pull right over into gas station and car stalls as I come to a stop in a side parking spot.
Engine won't turn over. Electronics worked fine but I gave up to save battery.

No warning lights , no flickering, nothing before it died.

Most of the car has 156k miles on it including alternator. Fresh pistons and timing everything at 120k. Fresh cyl head at 135k.

Car made plenty of power on my stg2 APR tune all the way until that last traffic light.

Time for a tow I guess? Closest reman'd alternator is Tuesday morning.

I see metal shavings that could have come from the pulley including on the frame rail nearby.

[Gunnark100]

Its hard to say via internet, but looks/sounds like alternator bearing died, i would tow the car, otherwise result may be fire also!

[Militant-Grunt]

Generally you have a red battery light come on if the car is not getting over a certain amount of voltage. That or it could be right on the threshold. If you have a multimeter, you can check the voltage while the car is running. If you don't have at least 12.8 on idle with no loads, its more than likely the alternator. Though it is possible you could have a corroded wire and getting voltage drop (though unlikely).

[Dub_prime]

Just replaced mine with a unit from autozone for about $220 with 20% off and $10 gift car with a $75 core, it was only about a 30 min job 4 bolts and a 16mm for the tensioner.

[pierreb]

I also have a q5 and just snapped a pic of the pulley area. Seems to look mostly the same.

I'm just hoping it's not something else. Car basically gave no indication of trouble beside the whining for 7 miles then a stumble then a full stall and now no turning over.

[kdaffy]

Seems like the alternator pulley went, but strange that there were no warning lights...mine died recently and when it happened my battery warning came on.

Amazon has Bosch for like $230. It's worth replacing the belt too since you'll be in there IMHO

Sent from my Nexus 5X using Audizine mobile app

[pierreb]

Got back to the car and scanned it. Got a code about the starter which was probably secondary. The car surprisingly did start but there was a racket from the alternator area and when I got to it there were sparks flying from the pulley area. I think we have our diagnosis lol.

The rest of the car scanned clean by the way. Nothing in Module 46. zilch. nada.

[Militant-Grunt]

Got back to the car and scanned it. Got a code about the starter which was probably secondary. The car surprisingly did start but there was a racket from the alternator area and when I got to it there were sparks flying from the pulley area. I think we have our diagnosis lol.

The rest of the car scanned clean by the way. Nothing in Module 46. zilch. nada.

I just re read your main post. So you had battery life, but the engine wouldn't crank at all? Any clicking while trying to start? Starters do fail on B8's. They corrode out, sometimes the rubbed whether strip between the starter and the block falls out. Water gets in and corrodes out the starter..

[jfo]

How about the decoupler pulley? It can fail independent of the alternator and is easily replaced for about $100.

[pierreb]

I'm putting a $150 alternator in there tomorrow morning. I think the starter just wasn't happy with the alternator. It cranked and started this morning.

[pierreb]

Update: new alternator is in and the car is running perfect. Took me 45 mins including dropping the 16mm wrench down the engine bay. Old alternator won't rotate at all so I'm thinking I'll return it for the $35 core charge.



Thanks everyone for the input.

[Mina08]

There is also another part of the alternator where the copper prongs where out and don't transfer the power to the battery, i think it is the regulator a black plastic part on the back of the alternator looking from the front of the car.

https://www.youtube.com/watch?v=QtyP7AyZxwg

[Dr. Awesome]

I'm putting a $150 alternator in there tomorrow morning. I think the starter just wasn't happy with the alternator. It cranked and started this morning.

Great to hear you got some help and you're driving free and clear!

edit: lol tried to quote your newest post, not this one!

[pierreb]

Yeah I'm still miffed the car had nothing to say about this at all in direct feedback via dash lights or via scan. Considering all the nags and nannies in this thing, I'm very surprised.