Fan Belt Problems!

Evening All.
Replaced my fan belt recently due to some horrible squealing and being very slack.
the new belt doesn’t seem to of fixed it, I tension it as much as I can and its great for 100 miles max. Then belt goes slack and squeaking reappears at high revs.

Is this common with these? What am I doingwrong/ any suggestions? Wonder if I need a new alternator?
Many thanks G

What engine ?

If it is not holding tension is is possible the adjuster bolt sliding in the groove. Use some shake proof locking washers with the bolt and it might improve things as they dig into the slider

Defender 200 TDI - I have put sprung washers on there but that doesn’t hold it

Gcornwall said:

Evening All.
Replaced my fan belt recently due to some horrible squealing and being very slack.
the new belt doesn’t seem to of fixed it, I tension it as much as I can and its great for 100 miles max. Then belt goes slack and squeaking reappears at high revs.

Is this common with these? What am I doingwrong/ any suggestions? Wonder if I need a new alternator?
Many thanks G

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Have you got all three bolts on the alternator in place. Including the one at the back that can get forgotten/come loose. I had a similar problem with the belt not holding tension. Turns out some idiot (me) had forgotten to but the rear bolt in on the alternator when I rebuilt the engine.

Have you checked that your pullies are in line? An offset pully will stretch the belt.

Col

Colthebrummie said:

Have you checked that your pullies are in line? An offset pully will stretch the belt.

Col

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On the pulleys point as well, if it slips it might be worth replacing the pulley. They wear a groove and the belt sits lower. A new pulley will grip the sides of the groove better and mean the slight loss of tension has less effect

My disco 200Tdi had similar symptoms when the alternator failed. I fitted several belts before the failing alternator was identified as the cause of the belt squealing and then coming off within a similar distance.

Thanks all, one final tension and a trip to the pub snapped the belt, fitted a new Dayco belt last night - seems to be holding for know! Thanks for all the knowledge!