Hi all,
Thanks for the tips.
Just to let you know, it was the belt.
Take a look a look at this!
This should have been an easy spot, save for the fact that from that front access
hatch I have you can't barely even see the belt at all.
Anyway, all good now, and I changed the alternator belt at the same time.
Just in case anyone else is doing this on a
3GM30. It's 14mm for the top alternator bolt, and 12mm on the nut behind it. It likes to spin as you turn the bolt so you will need both wrenches.
The bolt that allows the alternator to swivel is 13mm and is accessed from the rear. There no nut on this at the other end (at least in my case).
All
water pump bracket nuts are 13mm. 7mm for the small bolts that hold the back of the impeller cover on.