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Engine Knock?

1084 Views 12 Replies 5 Participants Last post by  Kip-on-truckin
My 2014 2500 3.6L with 161K on it has developed what seems to be a engine knock. Am I screwed?

I recently drove the van across country to Utah and after a few weeks of living here I started noticing the sound.

I have not done the oil since arriving but changed it a few days before our trip across. The van seems to run fine overall but sounds awful. The noise seems to dissipate at speed. I do have 2 codes, a P0420 - Catalyst system below threshold Bank 1 and P0430 -Catalyst efficiency bank 2.

I have not been able to diagnose if there is an exhaust leak due to the recent weather out here but it seems like it could be more than a minor issue.

link to video filmed today.

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Limited information, but the symptom/sign of the pentastar tick is a single cylinder misfire. If it gets bad enough, it will CAUSE cat codes (P0420,P0430) as the unburned fuel from the misfire gets into the cat. In this case though, your problem is more likely to be something other than the tick, because you have those codes in isolation. And that you have codes for BOTH cats at once is very telling. Given that your complaint is noise, I'm guessing you have an exhaust leak that's allowing BOTH cats to give wonky readings. There are other possibilities - it could be overfueling which would do that too, but it would result in other codes as well. Too much fuel would also sound loud and blatty, and you'd likely see black smoke or soot out of the pipe. The root cause of this problem is likely something very simple - an unplugged connector could make it overfuel, a wiring issue at the main computer.
 

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What I hear in that video is not pentastar tick. What I hear sounds kinda like flexplate, or kinda like a pcv valve. In short - there's an access panel at the bottom of the trans. Pop it, work the crank with a 27mm or crescent wrench and observe how tight the flexplate is to the crank. Should be zero slop. If that ain't it, test the pcv valve by pulling the hose on the valve cover, and plugging the valve cover side with your finger. If noise goes away, you've found your fix.
 
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I changed the oil yesterday and added a quart of Lucas oil stabilizer to see if that would quiet anything down internally but no change. The oil looked good and I ripped open the filter to check for any debris but it was clean as a whistle.

@Kip-on-truckin few questions:
1. Is it possible the cats are so shot that it's causing a severe pressure back up? Is there any way to test this? could I remove the bank 1 cat and start the vehicle and listen or would that just throw everything off?
2. At some point I am going to have to accept it could be a lifter issue. When that time comes, any recommendations on how to properly diagnose which bank it's on. I am thinking a stethoscope would help. Are there any particular ones that tend to be the culprits due to their location?
You can pretty much rule out cats - they arent going to make sound, at least not a sound like that.
You can improvise a stethescope with a piece of rubber hose, or a very long screwdriver or some such.
At this point, I would pop the belt off, start it, and see if the noise changes. Only run it for less than a minute. That test rules out everything on the beltpath.
 
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