Oil pump clicking noise

[Widebody]

Hi,
Any idea on why I’m getting a constant clicking noise in the oil pump after it warms up, nothing changes in its operation still produces the same oil pressure. It is an oil pump from China, the one with the belt reduction drive?

[Lil Giants]

Only when it warms up?

Is it belt drive? That's the only time I've ever noticed a clicking noise, either belt condition was poor or needed tension adjustment.