Thanks in advance anyone for their time. I’ve explored every corner of the internet trying to find the same noise.
Upon starting the engine there is a loud tapping, doesn’t sound like a deep knock or rhythmic lifter ticking. It started off very minor, and has slowly gotten much worse. It is loud enough to be heard by anyone in the immediate area, maybe a couple hundred feet.
In every instance so far, it diminishes until gone when all warmed up and the Jeep drives absolutely fine, as good as new in fact. nice and quiet. It is throwing no codes. There are no odors or smoke. I have eliminated the possibility of anti drain back valve, oil filter issue. The oil is fresh and sea foam was added.
One mechanic watched the below youtube videos and says the fact that it’s not rhythmic in time with the engine throws him off. Perhaps someone here can recognize what is going on?
When I turn the key with the gas pedal pressed down to prevent the engine starting the noise is present.
I’ve spent a few days trying to learn online all the various noises and causes, and come up pretty empty. If I had to pick one thing I believe it could be, It’s a loose timing chain banging on its cover and as the engine warms and oil pressure increases the tensioner is finally able to reel her in. But cant get anyone to say yep that’s likely it.
Editing just to add, not coming from the cats, which are bolted directly to block, unless the sound somehow travels or radiates from the rear to the front area of the engine.
First video, right after starting: https://www.youtube.com/watch?v=0p45DOBOBLg
Second video, after running a minute or two and calming down: https://www.youtube.com/watch?v=xvQs0mhRWcQ