Slight whining noise near engine.

[SneakyRussian]

Hey guys,

Near engine with open bonnet or whilst driving/revving above 4k rpm, can be heard light whining noise.
Reading from various places I assume it's dephaser pulley going? Also changing that I assume need to change the cam belt too? So we talking about what 500quid? :/
Nicely driven will it live for couples of weeks considering noise is mild and only recently appeared?

 

[SneakyRussian]

Edit: checked all fluids they are fine. But the motor did feel bit warmer than usual.. Maybe it's water pump? Would it make such noise

Edit2: now thinking of it feels jumpy and weird at low rpms when driven from cold until warms up in 5min. So it's gotta be the pulley huh?