2012 Grand Caravan with a random engine Knock (not tick) I can start it and there is no noise but then after a bit you hear it. Drives fine and only makes the noise at idle, sometimes under load and sometimes not. A slight rpm increase makes it go away.
Replaced the harmonic balancer and seal that was leaking. Upper valve train sounds good and even dove into bank 2 and checked the rockers that were all tight. 200,000 km on van. This can't be crank bearing ? Syn every 6000km Any ideas?

 

I have a 2012 GC 3.6L w/ 130K miles. I've had three bad rocker arms and all of them sound like a bad crank bearing. Although the rocker is on top of the engine, for some strange reason, the noise is MUCH louder under the engine, giving the impression that the noise is coming from the bottom of the engine. Don't overlook rocker arms, especially if you have a 3.6L. These are notorious for bad rockers. There's 24 of them, and 24 lifters. Further, a loose rocker arm can feel tight if you check it while the cam lobe is depressing the rocker arm.

 

Opened up the front, checked rockers and turned the crank so lobes were not pressing down. they were tight. Put a stethoscope on read admittedly only on the intake side of the cover and there was no noise there.

 

Did you check for a cracked flywheel there's been instances where some people have complained about some rattling knocking sound that ended up being a bad flywheel.

 

That's new to me, I'll check this weekend. Now that you say that I remember hairline crack I saw from inspection plate access but really couldn't get a good look from there.

 

If you seen a hairline crack in the flexplate that's the likely cause of your knocking rattling sound with the engine running and check under the hood the noise should be coming from the bell housing area.