Broke a fan belt October 2017 while holidaying. Had it replaced and continued my holiday. All seemed well until March 2018 when the fan belt broke again after only 2300kms added. My local mechanic on checking said that the bearings in the guides were worn and also the tensioner was bent which eventually causes the fan belt to slip off the tensioner and brake. He said this happens from either the bent tensioner being faulty or caused by regular excessive acceleration from stopped. This puts excessive load on the belt and tensioner when it tries to engage from the idle. Luckily in my case it was a faulty tensioner.

I took it back for him to check after a month and he said it is all running true now.