I'm trying to identify the issue causing this rattling noise. It only happens on Idle and immediately goes away at RPMs > 1800. It doesn't sound like the typical bore scoring noise.
and sounds like its near the alternator/belt area. Any ideas here? I posted a video on youtube:

Thanks in advance

 

That engine is really running rough. Pull the air filter box, remove serpentine belt and hand test all the pulleys and water pump, alternator. Check the oil fill pipe for any cracks.

 

Will do. I changed the airbox recently from K&N intake to a 997 airbox so I thought maybe I messed something up but I don't think thats the issue.

 

The alternator appears to moving around too much

 

That's a really good observation - check both mounting bolts and inspect the plate it mounts to carefully for cracks.

I had a belt shred soon after I bought the car and found this:




New vs old:

 

Yes, nice catch! If it is a broken alternator bracket, the movement could have compromised the bearing too.
Make sure you replace it with the beefier 997 bracket shown in Sleepy's pic (part #997.101.021.00). Before you check the price on the bracket, you should be sitting down with a stiff drink in your hand though...

 

How do you break an alternator bracket?

 

The sleeve that slides in as u tighten that bolt corodes to the aluminum so when someone prys on it to remove the alt it doesnt allow it to lift squarely and it puts too much pressure on that plate.

 

https://rennlist.com/forums/996-foru...r-bracket.html

 

Ha I’m coming back to this thread cause I found the issue and….. the alternator bracket broke and also shredded the belt.

I wish I kept getting emails about replies on this thread so I could’ve found the issue earlier 😂

Luckily I found a replacement bracket and will be installing this weekend

 

Add me to the list of people this has happened to.

I still can't believe how expensive that part is.

 

To those who had this issue, did you lose a lot of coolant when replacing the bracket? Did you have to do a full coolant flush or is topping up enough?
Should I top up with distilled water, red coolant or a mixture?

Thanks again!