2010 canyon 3.7 clatter noise

[jfnar]

I'll skip the long story of how I got to this point and get straight to my problem. I have a 2010 canyon with 3.7L 5 cyl engine. I bought this engine to replace a bad original engine. It supposedly had 90K miles and is in "perfect" condition. Got it installed and it had a lot of noise in the front. I replaced the belt, tensioner, and idler and made no difference. Next I replaced the water pump even though I couldn't find anything wrong with the old one and most of the noise went away. I thought I was in the clear until about a minute after I started it and a clattering noise started just like you flipped a switch. The noise seems to be in the upper front area just under the oil fill cap. After sitting over night I started it again and it happened just like the first time. It started out pretty quiet and after about a minute of running the clatter noise started again. If it was an older vehicle that I'm a little more familiar with I would say it sounds like the valves need adjustment. I don't know much about newer engines. It has new oil and filter with 1 qt of Lucas in it. Since I don't know how long the engine has been sitting I'm planning to drive it awhile and see if anything changes. Any suggestions or ideas would certainly be appreciated. I like this truck but this engine is driving me crazy. Thanks for your help.

[EVRLET]

Since you said it sounds like the valves need adjusting, what you’re experiencing could be a bad lifter(s) tick. Common issue with LS V8s, so maybe that’s it. People with 3.7s have experienced issues with lifter tick.