Squeaking noise on lock/when cold

Hi everybody. Looking for some advice about my 2002 1.9 Tdi SE, PD100 engine (ATD I think) with aircon. It's concerning a squeaking noise which occurs on full lock and also just after a cold start. I thought it would be the alternator/power steering belt so I changed that and it seemed to go away but it's back.

Does this engine have alternator pulley problems or is it going to be a slack tensioner which needs replacing? The tesnioner is wobbling up and down when it's idling, as though the spring may be tired and not pushing as hard as it should. It's done 99,000 miles.

Any advice appreciated.

It is most likely the free-wheeling pulley on the alernator - they are very common.

easy enough to check. just use a small pointy thing to see if you can turn the alternator fan through the casing. it should be able to turn in the direction the engine would spin it, but not the other. if you can't turn it, you need a new one, which i can pretty well say for sure you do.

Two Questions on this one:- (i) Do all PD100 engined Mk IVs have the freewheel alternator pulley? (ii) If it's the pulley, why do I get the squeak when I put load on the power steering i.e. full lock (it stops when the steering is let go)?

Yes i think they all have the free wheel bearing. When you put load on the steering, the power steering pumps works hards which is connected to the Aux drive belt. My MK4 had this problem and changing the free wheel bearing on alt solved it right away. I did read one post in here or another MK4 site, that the power steering fluid level might be too low or might need changing, so might be worth checking that before the £35 of a new bearing.

Thanks for the replies; I had another think about it and realised the load on the power steering would put tension in the belt and cause the squeak. Checked under the bonnet and yes it has a freewheel pulley and yes it's jammed. Sourcing a part today, the tool to change it is on it's way so it looks like a little job coming up for the bank holiday weekend.

Hello again. Rounding up this one, my pulley arrived today from GSF and so did the Laser 3307 Alternator tool - M10 spline 1/2" D. I eased back the tensioner with an adjustable spanner and locked it with a 4mm drill shank through the holes. Prised off the plastic cap from the pulley and put the Laser tool on my 1/2" socket T-bar then eased it into the pulley/alternator shaft - not much room because of the washer pumps. Used the same adjustable on the 17mm AF bit of the tool and squeezed the two together to apply pressure. It gave suddenly with not too much effort and then was only finger tight - came off easily. Reverse process to fit the new one - tightened it as hard as I could with the drive bar and spanner then put the new cap on. Released the tensioner, checked the belt was on properly and started the engine - presto, noise gone and tensioner movement much reduced. No noise on full lock so problem solved; thanks to Zollaf, M and Geoff Eeles for the contributions.