fluttering rev counter

hi all,

sold my disco a while back now but a mate of mine is now having a few problems with his 300tdi (ill never get clean hands!) anyway..
been having a squeek from the water pump for a few days and on inpection it has a little play in the pulley-not much but its planned to change it at the weekend as we know they dont last long once they start going. he called round today because the rev counter started bouncing and waving on idle-fine when revved. cleaned the plugs and wires on the back of the alternator with brake cleaner and gave behind the pulley a quick squirt, the squeek stopped and the rev counter whent back to normal. couple of mins later and the squeek came back and the counter bouncing again!
last service about 2-3 month ago the guy said he had checked everything over and the alternator was ok.
is this a sign the alternator is on its way out or could it be if the water pump is leaking from the bearing onto it and gunking it up?
any ideas would be a big help. cheers

Sounds too me like the belt is slipping

UPDATE:
just rang to tell me, the rev counter stops fluttering when the lights are on- turn lights off and it starts dancing again

Richard Martin said:

Sounds too me like the belt is slipping

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thats what i thought, but whats this about the lights?

go to the other side and take a look at my thread titled:
disco intermittent / fluctuating rev counter.

if every thing else fails try that

Loose wire on the back of the alternator is that viv???

vivnap said:

go to the other side and take a look at my thread titled:
disco intermittent / fluctuating rev counter.

if every thing else fails try that

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sorry i may be dumb- other side??
the search dosnt bring anything up with that title

daza said:

sorry i may be dumb- other side??
the search dosnt bring anything up with that title

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the other side is onelaugh

lerk said:

Loose wire on the back of the alternator is that viv???

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no, they get a fault inside the instrument cluster thats dead easy to rectify.

How did you sort it as I have this problem !!

Alternator change.

daza said:

UPDATE:
just rang to tell me, the rev counter stops fluttering when the lights are on- turn lights off and it starts dancing again

Click to expand...

Liberal spray of WD40 or similar inside the alternator solved it permanently for me.

Nigel1943 said:

Liberal spray of WD40 or similar inside the alternator solved it permanently for me.

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Is there nothing that WD40 cannot fix

Spade connector on back of alternator clean it. if still same check wiring. and replace connector.