I have a 2005 Silverado with the 4.3 V6. After warm up I notice a ticking sound comming from lower end of motor. Not so much top of the motor.... Just when I bend over and stick my head in the wheel well.... or slide under the truck.... It only has 38,000 miles.... It doesnt do it when cold... Just after warming up... Oil pressure needle sits just below 40 mark give or take... so its good im guessn and i change oil every 3000 or so... Im a die hard for maintaining my vehicles.