Marvel Mystery oil, or a similar "top end" lubricant, after an oil/filter change.
Depends on the age and valve system on you car.
They could just need adjustment.
Modern engines use hydraulic valve lifters. If these persist in rattling after warm up, you could have a worn camshaft and/or vlave lifters.
check the spit valves
Take it to a mechanic.
Is your oil level?
replace the exhaust.gmjim
Replace the valves guide seals.
Rattling under the hood can be something easy to fix to something bad. It could be loose bolts, bearings, pulleys, or it could be interior in the motor.
Bash it with a rubber mallet while it is rattling. Seriously. Mine stopped.
sounds like your valves are rattling check your oil
Need more info. It can be $5 for a Tire valves to $2000 from bent valves/damaged pistons.
You probably have a loose blower wheel. Call an AC tech to fix it.
the muffler rattling? the muffler rattling? the muffler rattling?
you cant if rattling noise occures its a worn lifter very common on 3.1 motors