I think I know the answer to this, but wanted to check here and see if anyone had any thoughts. Had the rattle up by the supercharger, went in and pulled it off to replace the coupler. Sure enough, worn coupler. New one is nice and solid. Was going to put everything back together, noticed the 3 pin drive hub on the impeller side had a bit of play side to side- pulled out the indicator, almost exactly .001" (.025mm) of side to side play. trying to move it Front to back is rock solid, gears feel rock solid, and snout feels solid, but that one needle bearing in the front has a thou of play. I'm due for a Supercharger rebuild with new bearings, aren't I? Before I tear everything apart, I figured I'd ask. Rattle was exactly as described with the coupler- BB's in a tin can kind of sound.
Thanks!
2016 F Type 3.0 with 65k miles

 

I don't think there are any needle beatings at the front, I think you will find they are ball races and I would suggest that one thousandth of play is to be expected.

 

I think you are correct that the front/snout bearings are ball race bearings but there is no doubt that the rear/case bearings are needle type, see here for example: https://www.ebay.com.au/itm/18329535...Cclp%3A2047675

 

My apologies, did a quick look at a rebuild kit and assumed the needle bearings were at the front. .001 in a ball bearing is different, but probably not miles off from spec.
For the record, this is the sound that I'm having a problem with. Only when hot- Fine when cold, fine even after a short drive. This was taken after sitting in traffic with the A/C on for a while. It almost sounds like fan hitting plastic more than anything, but can't be sure. No other problems, stays cool, drives great, just a bit of noise. Definitely top of engine, gets quieter toward the fuel pumps so it's not them. This is with the new coupler.
Hopefully this attaches okay.

 

Hate to say it but sounds like timing chain issues maybe....

 

Kind of does, but I'd think it would be more consistent- as well, I don't think it would completely disappear when cool, and even when it's hot it's not always there. Drove for 15 mins back to the shop last night, Didn't hear it. As soon as you come off idle it disappears. Sometimes it will cycle for a bit, you'll hear it for 5 seconds, then you won't. The only time it's consistent is it's never noisy when cold.

 

The only reason I can think of is that one of the tensioners has got a leaky seal which doesn't leak when the oil is thick but leaks when the engine has warmed up due to reduced viscosity. And it may leak intermittently perhaps. Maybe change the oil to 15/50 and see what that does? As you come off idle the oil pressure will increase so that bit makes sense too. Tensioners are reasonably easy to swap out.

 

FYI This ended up being the Accessory belt tensioner- No noise when moving the arm with a ratchet cold, but as soon as the car warmed up it got notchy and loud when turning with a socket. Very relieved, easy fix.