Worrying Rattle (update)

[Bo Bo]

Thanks for the input guys.
Had another listen earlier & pretty sure the noise is coming from the aux belt area.
Took it to the battery/alternator guy I've been using for years. It's charging OK & he says if it's the alternator bearings then the rattle would be there all the time to some degree, but there's no noise when it's warm. I plan on changing the waterpump next w/e, so will have to live with it & I'll update then.

[Matchless]

You can check the alternator bearings with a 'listening stick'. You need a very long screwdriver or metal rod, rest one end on the suspect item and press an ear to the other end, the bony bit immediately in front of your ear-hole is quite sensitive.
You can just see the rear alternator mounting bracket from above, use this to check the rear bearing and anywhere on the alternator front casing to check the front bearing but be careful, you wouldnt want to slip.
A noisy bearing race is quite distinctive when checked this way but unfortunately there is no way to get to the water pump to check it.
The noise seems to be changing with electrical load but this doesnt necessarily mean the alternator....the water pump etc would also 'feel' the increased load on the belt.

[Bo Bo]

The noise seems to be changing with electrical load but this doesnt necessarily mean the alternator....the water pump etc would also 'feel' the increased load on the belt.

Cheers, I'm no expert (despite what it says on the left!), but this is what I suspected.
I'll try the listening thing before I tackle the waterpump.

[Hillper]

Be very, very careful with the listening stick.

I did this once with a short one and my 'hair unit' got caught in the belt.  It spent several days circulating the pulleys before finally flying out and landing in a tree.

[Marks DTM Calib]

One question I woudl ask is......its not the air injection is it, do check it for leaks etc and make sure the oen way valve is working ok.....the stainless tubing on the front isn't rattling on something is it......

.....having said that, we have already determined it goes away when the aux belt is removed.

[Bo Bo]

Quick update, just swapped pulleys with Timbuk & the rattle is still there as we thought it would be.
So it looks like it's the tensioner itself.
Mark; I've had all of the air intakes out when doing the waterpump, so they're OK.