Fan belt/ Alternator belt squeal on start up

My 05 jim has a rather squeaky fan or alternator belt on start up, worse when I have a few electrical things running! Belts look fine and seem nice and tight, could they just need a spray with Wd40 or something?

Make sure the belt is tight: I just go for it is tight enough when I can just twist it 90 degrees.
If that doesn't work, fit a new belt and clean the pulley grooves thoroughly with a wire brush.

Don't use WD40 it damages rubber. In fact dont buy WD40, it is useless except to displace water. For penetrating oil, use diesel or plus gas. The best universal spray in a tin is GT85.

I spray the belt on The Other Car with pledge furniture polish: the silicone stops the squeal, it smells nice too and is only 99p a can

One day I will fit a new belt, but you have to dismantle half the car to do it and the pledge is easy to spray from the top

Possibly alternator or another aux nipping up causing the belts to slip? Try getting someone to start it up with your head under the bonnet to try and localise it if both belts are all in good nick and tensioned correctly?

Jack.

you will find the belts either need more tension or possibly the rubber has went hard and is squealing over the pulleys and then it needs changed

facade wrote: Make sure the belt is tight: I just go for it is tight enough when I can just twist it 90 degrees.
If that doesn't work, fit a new belt and clean the pulley grooves thoroughly with a wire brush.

Don't use WD40 it damages rubber. In fact dont buy WD40, it is useless except to displace water. For penetrating oil, use diesel or plus gas. The best universal spray in a tin is GT85.

I spray the belt on The Other Car with pledge furniture polish: the silicone stops the squeal, it smells nice too and is only 99p a can

One day I will fit a new belt, but you have to dismantle half the car to do it and the pledge is easy to spray from the top

Thanks for the suggestions guys! Shall check the tension again tomorrow but I recall they were pretty damn tight!

I may try the furniture polish trick though!

if the belt is squealing but is adjusted properly the its time to change it. spraying stuff on belts is on a par with putting eggs in radiators and tipping thick oil in to quieten noisy motors. old salesmans tricks to pass on dodgy motors.