Sounds like a noisey tappet when engine cold 2.5 1997

tap usually associated with lifters when vehicle warms up oil thins out and a bad or worn lifter will make a tapping noise --other oil level low --oil needs changing --low level will starve rockers/push rods/and lifters which will also cause tap ---damaged /dirty{sludge oil can cause same problems

I DON'T KNOW HOW MANY MILES ARE ON THE ENGINE. Found no bulletins for noise concern
Intake tappet clearance should be .006"-.010" and
Exhaust clearance should be .010"-.014"

sounds like a tappet,could be a ping caused by low grade of gas. hows the oil pressure. sometimes when oil pump is weak it will cause this when car warms up. will also do this if car is overheating...hope this helps some and good luck.

rev engine upto 3500 and hold it for 20 secs or so the hydrolic tappets should then reset...

The tappet clearence should be in the owners handbook but it's a bit early a tappet noise from the engine (2006) ! Check oil level and change if it's overdue a service is definately worth a look ! Good luck

sounds like your tappets need adjusting ,

Usually a ticking from the engine is caused by oil not coating the tappets. Tappets are the rods that control the intake and exhaust valves. Once the engine warms up oil is circulated to those parts and the ticking stops.
Mopar is famous for that

Try changing to an heaver oil first,if your using 10-30 go to 10-40,see if this helps,before looking at the valves.

SOUNDS THAT YOUR TAPPETS ARE NOISEY COULDN'T TELL YOU IF ARE ADJUSTABLE OR THEY ARE HYDRAULIC TAPPETS NEED TO REFER TO HYUNDAI.

8 valve engine ,intake cold 0.13 to 0.17mm hot 0.23 to 0.27 exhaust cold 0.16 to 0.20 hot 0..26 to 0.30 mm 16 valve engine (intake and exhaust) cold 0.13 to 0.17mm and hot is 0.17 to 0.21mm