I think the supercharger isolator on my supercharger is on it's way out. Over the past 2 or 3 months I've noticed what I think is a progressively louder "clunk/rattle" sound when I shut the engine off. In the past two weeks I've also noticed a low "hum" while the engine is running, it almost sounds like a bad bearing.

Below are links to two videos I uploaded to YouTube. This is after the car has been driven for about 25 minutes. The first video is just startup, the second one is the one I'm more interested in. You can hear the "hum" slightly when I direct the camera at the supercharger snout pulley but it's hard to hear it over the general racket of the engine on video. At the end of the second video you can hear the "clunk/rattle" sound right after I turn the ignition off. Can anyone comment on if this engine/supercharger noise is normal on the supercharged V8's? My warranty is up in 4 months so if it's an issue I'd like to get it resolved before it expires. Thanks!

Startup - Idle and Shutdown -

 

These are pretty noisy engines. I did not really hear anything concerning from a noise perspective? Isolator could be going but does not sound that bad. Maybe others know better.

DC

 

8.5.1

Thanks, DC.

 

Agreed, both the start up and the shut down sounded OK to me.
I didn't hear the classic worn coupler "clonk" on shut down, instead I heard the normal "relay switch off" click.
Take it from someone who had been there done that, the worn coupler noise at start up and idle and shut down is loud, distinctive and obvious!

 

I just noticed that DJS posted a video of a bad one https://www.dropbox.com/s/1m09fqw9cn..._3149.MOV?dl=0

Is the "clunk/rattle" sound at shutdown a normal supercharger sound? I've only owned and worked on NA and turbocharged vehicles so I have never really listened to the sound of a supercharger during engine shutdown.

 

Sounds pretty normal to me as well. The shutdown rattle is common to snout driven SCs. The direct driven SC on my MINI makes no such noise. A bad coupler is going to sound like hammer on an anvil. Otherwise it will sound like a stir ball in a paint can.

 

Thanks, all. I'm probably just being paranoid knowing the isolators on the TVS units are sometimes an issue. I appreciate the responses.

 

If your going to repair it with a new isolator, do what I did, but a new snout/with the pully on it for $350 and then get the smaller pully and put on it and the tune for it from Stuart at AP. You will have more fun. Also, while your "in it" with the blower off, replace the shitty heat pads underneath for a better version. You might as well change the Y water pipe because they eventually leak too.