The engine parts are rubbing until the engine oil pressure builds up and the oil starts to lube the parts. Old oil, wrong viscosity, or a clogged filter can cause this to be worse than necessary.
lifters
The fuel injectors make the ticking noise you hear at startup, especially when the engine is cold (colder temperatures).
What causes ticking, check engine light, and the check gauges sensor to come on in a 1999 Dodge Durango 5.2L SUV?
The ticking sound is coming from the valve lifters. When the oil filter is changed, air is introduced into the system, which causes air bubbles to form in the oil. This causes the valve lifters to "leak down", which is what causes the ticking sound. It can take several days for the bubbles to dissipate. It's annoying, but harmless.
Possibly just an adjustment on the rockers. Hydraulic system. Hopefully that's it.
The ticking noise could be worn out rocker arms under valve covers. Switch to heavier weight oil if ticking noise subsides that could be your problem. This is usually a sign of a high mileage engine. Worst case scenario would be weak oil pump not getting oil to top of heads.
I have the same ticking noise and it seems to be louder on hotter days. I was told by the service tech it's due to the synthetic oil being thinner. I have my doubts, but that's what they said. Still researching for the answer myself.
the ticking noise is a small exhaust leak close to the exhaust headers or exhaust pipe near the engine.
Could be a weak oil pump. The reason it is ticking is that the oil is not flowing to the lifters when it's cold. It's not that big of a deal.
Take it to a mechanic
The ticking noise is the metal cooling.
if ticking noise is in engine, u most likely have a worn hydraulic lifter. check oil for correct volume and viscocity