6.5 Diesel Clunk When Shutting Off Engine

[RayGunSlayer]

So when I shut my engine off I get a pretty loud clunk noise. I read some posts saying that it’s the crank puller or harmonic balancer. Well my crank pulley rubber is in great shaped with no cracks and I can barely move it at all when the engine is off. Like maybe a 1/4 of an inch. I don’t know how to check to see if it’s the harmonic balancer. Just curious if anyone else has had this problem before. I should also mention that it is not every time that i shut it off. Out of like 10 times it’ll happen like 6 or 7 times maybe

 

[Milcommoguy]

I am not so clear on what your moving. Back and forth... side to side... left to right, round and around ??? etc. Might look around at alternator bolts, brackets... those things that drive off the belt or belts. Engine / transmission mounts. exhaust system. It's a guessing game from here. When shut down they do come to a quick stop.

Could be anything... got be something, CAMO

 

[RayGunSlayer]

I am not so clear on what your moving. Back and forth... side to side... left to right, round and around ??? etc. Might look around at alternator bolts, brackets... those things that drive off the belts / belts. Engine / transmission mounts. exhaust system. It's a guessing game from here. When shut down they do come to a quick stop.

Could be anything... got be something, CAMO

The pulley that is connected to the crankshaft right in front of the harmonic balancer. It won’t move in any way except like trying to twist it clockwise or counter clock wise. I will definitely look at the other accessory drive pieces and see if any bolts are loose or anything. As far as engine and transmission mounts. They are both brand new, like 300 miles old, and fully tightened down. Everything comes to a complete stop when it’s shut off. Not like a sluggish or slowing down stop

 

[Action]

..........Everything comes to a complete stop when it’s shut off. Not like a sluggish or slowing down stop

My motor stops when i turn it off. It does not continue to run and shut off when it wants to. Newer serpentine belt models have a clutch in the alternator pulley, so it can slow down on its own, when the belt stops moving.

 

[Monkeyboyarmy]

Is this a separate clunk from the start system control box clunk?

 

[RayGunSlayer]

I will try to take a video of it and post if so you all can hear it. It sounds kind of like a piston kind of clunk. My hmmwv runs perfectly other than this noise

 

[RayGunSlayer]

Okay I guess I really never noticed it but yes it does slow down a little after I turn it off and then the clunk happens. Here’s a video. Thanks for any input you all!

 

[RayGunSlayer]

Also my 6.5 is a serpentine setup so what you said Action makes sense.

 

[Retiredwarhorses]

this seems to be normal, I have many many hmmwvs, this noise seems to only be present on the older serp setup where there is no clutch pulley on the 200amp.

 

[RayGunSlayer]

I appreciate the info Retiredwarhorses! Just didn’t know if it was something I needed to look into or not especially since it’s not constant.

 

[Gunnlogi]

My motor stops when i turn it off. It does not continue to run and shut off when it wants to. Newer serpentine belt models have a clutch in the alternator pulley, so it can slow down on its own, when the belt stops moving.

My 200amp will spin down after I turn off the engine, but it's sounding like it's dragging for lack of a better term. I don't think that's normal (for me with this truck it has done it since I purchased it, but in thinking the bearings are going?)