Topic

I've just gone out to check the tension of my alternator drive belt. It should be fitted as shown in the first picture taken from the Workshop Manual.




But it is actually fitted as shown by the green line in the picture below.





Now would it hurt to leave it fitted as per the second picture or should I take it off and fit it the right way. It's been working OK for the past few thousand miles.

The whole point of a idler pulley is to apply tension on the slack side of the belt.
When a belt is driven by the crankshaft pulley in is pulled along thereby producing tension in the belt between it and the components that it drives before it as it pulls the belt that drives them.
So any slack in the belt will occur after the belt has been pulled and is now being pushed into a state of compression.
This slack could cause a lack of traction of the belt to the pulleys or even cause the belt to fly off the pulleys altogether.
Having the idler applying tension on the pulling side is the least effective place to do it's job and will be applying excessive load on the idler bearing.
The ideal position for the idler is on the slack side to the driven pulley and it is always preferable that the idler should always be placed between the pulleys that are furthest distance apart.
You may find the belt has been stretched to much now of allow proper tension to be applied by the idler so I'd replace the belt when I change it back to it's proper route.

Yep, totally agree!

Personally I would replace the belt sooner rather than later.

Also, if you look at the angles on the second pic, there is less surface area on the pulley of the alternator which would make for less grip and the alternator would slip easier under load.

Thank you for your advice. I've now ordered a replacement belt that I'll fit the right way up.

When you do change the belt, turn the idler bearing by hand and note how it feels or even sounds.
If it's good it shouldn't make any noise and it should turn smoothly.
If it makes noise, and/or turns over lumpy, gravelly, rattly or scratchy the bearing is buggered.

Now there's another thing to check! I'm not sure if mine is on correctly either.
First I'll have to check my pic files to see if they show how the belt is on the idler. Failing that it will be wheel off, cover off and check.

Thanks guys!

EDIT: Looks like I'm good to go!

Considering the cost, I would replace the belt an set it up the correct way, also check the tensioner bearing, if unsure, replace that too