What are the typical causes for a noisy (squeaky) cambelt? The waterpump and alternator are not the culprits. When cold the noise disappears but when run to normal temp the squeak returns.

The cambelt tensioner and the belt itself are new. I'm running without the balancer belt (the shafts are NOT locked).

I've had this noise for a long time but after recent cambelt change I decided to get rid of it once and for all, but not yet successful.