My 911 might have died today?

[Bkresse]

I was driving steady at ~3000 RPM's in 4th gear, when I immediately began hearing a chunky grinding noise from the engine. It was on and off for the first 20-30 seconds while the motor seemed to still be able to rev appropriately, then the noise became continuous until I shut it down.

I quickly grabbed my phone and recorded this video for reference.



I'm anxiously awaiting for news of its condition; however, the shop isn't open until Monday. In the mean time, does anybody have an idea what this may be? Cost? I'm almost too afraid to ask.

I've always enjoyed reading the information that everyone shares on this forum and I'll appreciate any feedback while I wait.

Thanks!

[gregwils]

Interesting. It doesn't sound catastrophic to me, but the noise isn't terribly clear. The engine continues to turn over and we're not seeing plumes of smoke. Please post the result, we will all be curious to know.

Anyone else have a thought?

[kidrock]

chain ramps?

[911Freak]

So, besides the sound engine was relatively smooth? If so I'd vote for chain tensioner/s failure as that sounded very similar to my SC when one of the tensioners collapsed...

Think ball bearings in a coffee can, right?

Hope it's only this and there isn't any additional damage and you get away with only replacing the tensioners, ramps and maybe sprockets... (under 2k)

Keep us posted on what the mechanic discovers, fingers crossed for you

[keitho64]

Does the sound change when you push in the clutch? Is it possible the noise is in the gearbox?

[hcoles]

I would not try to start it again.
You might see if the alt. spins nicely with the belt off.

[mossguy]

CV joints?

[DRACO A5OG]

Chain Tensioners, as Kidrock stated it may be a failed tensioner ramp and the chain is rattling against the housing.

BTW, what type of oil are you using?

Jim

Oh yeah, welcome to the board sorry you had to join on a terrible note

[budge96]

as prior posters mentioned likely some tensioner pressure related failure..

Not catastrophic despite sounding as such,what was your oil pressure and level at the time?

[Bkresse]

Thanks for the all the feedback. I really appreciate this forum and all the sound advice and experience that is shared.

I didn't realize that as a new member that my post would take 1.5 days to actually be approved to be posted to the forum. So a lot has transpired since I originally wrote the post/question. First, I added the question on another forum that posted it immediately. I began getting feedback and as a result I began testing some ideas.

I removed the fan belt and rotated the fan. I was very happy to find that rotating the fan counter-clockwise created a grinding clunky noise that sounded as if it could be the source. However, rotating clockwise... no noise. I wasn't completely convinced so I dug a little deeper. I removed the a/c belt and then the fan. I fired up the engine, no noise! I shut it down ASAP.



Next, I rotated the alternator shaft back and forth, the noise appears.



I'm convinced that this is the source of my issues. Unfortunately, I just couldn't believe it was going to be the alternator because a new reconditioned Bosch was installed in late August. In hindsight, it should have been my first suspicion, but it wasn't. I went to total engine failure in my mind. Ive never been so happy to be wrong!

I got the car home and removed the alternator. I'm going to take it to the parts department tomorrow and exchange it for a new one. My Bosch warranty should cover the cost. I'll replace it and hope for the best. I may even take the opportunity to have the fan and fan housing powder coated while it's disassembled.

Again, thanks to everyone!

[70SC]

Check the fan hitting the fan shroud . Bad bearings in the alt. Hopefully

[ant7]

Altenator bearings...
Anthony.

[arry911]

altenator bearings +1

[Bkresse]

I appreciate everyone's feedback on this problem. I posted a followup but I believe it hasn't hit the forum yet because it had links in it. I've come to find out that because I'm a new forum user, I'm limited from adding posts with links until a moderator reviews them. So I apologize for the delayed reaction to your feedback.

A lot has happened since the problem arose and based on feedback from the forums I was able to diagnose and isolate the issue.

It was an alternator bearing issue. Once the alternator went (brand new remanufactured Bosch installed 6 weeks ago) the fan began rubbing the housing. This created a combination of noises that got me thinking the worse. Admittedly short sighted, I discounted the alternator as the source because it was new and the noise was seemed substantially worse than a bearing. In hindsight, it should have been my first suspicion.

Several of you guys nailed it. A bad alternator bearing it is.

Zimm's in Bedord, TX. Is replacing the alternator today and I should be back in the saddle soon.

What a turn of events for the best case scenario. The tow was covered by roadside assistance, the altnator is under warranty, and I have help to perform the labor. I was contemplating a refurbished engine at 8K or so and end up at zero cost after it's all said and done. I've never been happier to be wrong.

The resources on these forums are tremendous, thanks to everyone for your help and support.

[tevake]

Whew That is good news, happy for you.
There sure is a lot of help to be found here.

Cheers Richard