Cold start squeal. Replace harmonic balancer?

Got a slight cold start squeal that just popped up. Not sure if you will be able to tell anything by this video or not. Let me know your thoughts. Thanks.

It doesn't sound like it "squeaks" quite at the rate that would make me think it's a roller, water/ps pump, etc.. Like perhaps a damaged spot on the serpentine or timing belt? I'd check the serpentine belt first. Consider that after sitting overnight, running the glow plugs and starter motor, the alternator is working harder for the first few minutes to replenish that power. The extra strain on the serpentine belt could manifest in a squeak like that. It would be easy to pop that belt off and see if the squeak goes away.

Probably ought' to check the timing belt too.

If you can see your balancer from the fender well, my car is missing the side cover and belly pan, take a silver sharpie marker and mark a straight line on the balancer across all three sections of the balancer. Like a radius line in a circle. Start engine and let run for a min or so. Stop engine and look for your mark. If balancer is slipping you mark will be broken. Your video sounds like a hardened serpentine belt to me. A slipping balancer sound horrible and is real loud, your noise is mild.

Me and my mechanic are actually troubleshooting a similar noise that I have since months. It's only disappearing with the serpentine belt off. A new alternator pulley did'nt have an effect. Seems to be internal alternator bearings and I'll probably change it for a rebuilt unit. An alternator can be rebuilt locally but with parts of lower quality than Bosch's.

In the meantime, don't do like me and depart for a distant trip with an undiagnosed squeal: few years ago I had my water pump fail at the worst possible place in North America: at the very end of Transtaïga road...

I have a similar issue. I bought a new tensioner pulley thinking that may be it. Havnt gotten to install it yet but maybe sometime this week. I figured bad bearing or something but after reading this I think you may have a better idea.