Squeaky water pump.

[disco maniac]

my disco has recently started to squeak from the water pump pulley, it only does it occasionally.
when i spray wd40 onto it stops for a short while ( i suppose until its all been flung off).

is it a sign i need a new water pump :(

[Budgie]

If you've got a 300 TDi then make sure it's the pump before changing it as there are a few other problems that make the same noise and most are coming from the drive belt. If you are spraying WD40 onto the water pump (not the pulley or belt) then you could be right. the good news is that a new pump is only about £35.  

The drive belt will "squeel" if the tensioner pulley is slightly out of line, this puts a glaze on the flat suface of the belt and this makes a noise as it straightens up over the PAS pump.
If you look down the line of the belt, from the battery side, it should be straight - if the belt is deflected at all then it could be this that's causing the noise. WD40 on the flat surface of the belt will stop the noise.
A quick sort is just to change the belt and the noise should stop. The best one for this is to put a 1-2mm spacer behind the body of the tensioner (where it meets the front of the engine block) to bring it back in line.

The bearings in the drive belt tensioner also make a nasty squeel when they are on thier way out, WD40 into the bearings should stop this but it needs changing! Same goes for the PAS pump.  

[disco maniac]

thanks budgie, thats a big help. :)
we're off to malvern tommorrow so i need to get it sorted today.
if the tensioner does need a spacer to bring it back in line - what would make it go out of true in the first place. :?:

[Budgie]

It's when they get older. The strain you put on it to loosen it off when changing the belt pulls it off line. Newer ones tend to go back in line but sometimes, if you pull it "out" as well as "round" to loosen it, it can move out of line.

It's normally easy to see, more so if you've not got Air-con fitted.

Provided it's not the water pump then a simple change of belt will do until you have more time to look at it.  
If you can find some way fo taking the glaze off the smooth side of the belt then that will also work in the short term.