fan belt tension

[PYNEY]

hi all

anyone know the correct tension for the fan belt ? s3 v6
sierra manual 4mm
steve heath 20mm

when i know the correct tension distance is this when its pulled one way or in both directions

cheers keith

[TOPTON]

I've always worked on the twist it through 90 deg and no more principal. It's never let me down and I have never read a manuals settings for a belt

[phillpot]

4mm sounds a bit tight to me but 20mm a bit loose Maybe 10mm each way would be about right?

Must admit I never actually measure it, just get a feel for it.Pull the alternator up by hand, no levers or pry bars, and tighten.

Tight enough it doesn't squeal or "wobble" excessively when you rev the engine but not so tight it will Knaker your alternator or water pump bearings in no time.

[wizzer]

As Topton says I was always taught twist 90degs not so you are forcing it just easily turns 90 but not 180!

[PYNEY]

cheers guys