2007 Altima Click after startup. Please Help

[oartyo417]

Hey guys,
Brand new to the forum. Am excited to talk with other Nissan owners about common issues and upgrades. i do have a question about my 2007 Altima. the car starts and runs flawlessly, i am very happy i chose another Nissan, after each cold start even sometimes warm start, there is one single loud click coming from the engine bay. it seems to be coming from underneath the exhaust manifold heat shield. it sounds almost like a single metal to metal bang/tick/click. it only happens once and doesn't compromise the performance in any way. it doesnt sound good and is noticeable. it happens anywhere from about 30-90 seconds after startup (while the engine is still warming up). my 2.5s has 58,700 miles and i was consider bringing it to the dealership before the 60k warranty expires. if anyone can please help that would be great. Thanks