Weird ticking sound all of a sudden

2006 5.9 24v cummins just started making a weird ticking noise. It happens most on cold starts but not immediately, it starts once the ECT reaches about 95°F and stops anywhere from 115°F - 140°F, it almost sounds like something is caught in the fan or something, like a scratchy clicking noise, other than that sound the truck runs perfectly. And when I say cold start I mean it sits overnight and them I start it in 30°F - 40°F. Any advice is appreciated, thank you!