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Discussion Starter · #1 ·
Curious, since I just bought a 6.5L 3500 of the 96 model year and harmonic balancers seem to kill these engines. How does one tell if the harmonic balancer is bad without having to take stuff apart? Am providing a video of the engine running during shutdown, as I read somewhere that a "thump" at shutdown is one main symptom of a bad balancer. Don't know what that "thump" is referring too, and whether or not my engine does it. Much thanks. Truck has 220,000 miles on it. The buzzing in the video was just my phone vibrating with the truck, sorry.
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Welcome to DieselPlace
The first picture you posted shows enough evidence of a bad harmonic balancer.
If you look on the right side of that harmonic balancer you will see a strip of rubber that is warped from being oil soaked.

If you replace the Harmonic balancer you will need to replace the Crank pulley as well because it also contains rubber that has been exposed to oil.
 
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Discussion Starter · #3 · (Edited)
Welcome to DieselPlace
The first picture you posted shows enough evidence of a bad harmonic balancer.
If you look on the right side of that harmonic balancer you will see a strip of rubber that is warped from being oil soaked.

If you replace the Harmonic balancer you will need to replace the Crank pulley as well because it also contains rubber that has been exposed to oil.
Thanks for your response. One last quick question for you, is it too worn out where I need to urgently replace it, or can it hang on for a bit? I drive it just for commuting to and back from work, with no load on it. At this time I really can't find any time to send it to be fixed as I can't find myself capable of fixing it myself, looks too much of a hard task. Thanks so much for your help and advice my friend, really do appreciate it.
 

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Thanks for your response. Is it too worn out where I need to urgently replace it, or can it hang on for a bit? I drive it just for commuting to and back from work, with no load on it. At this time I really can't find any time to send it to be fixed as I can't find myself capable of fixing it myself, looks too much of a hard task.
I would change that ASAP.
Oil soaked rubber will break down and become soft ( which is what is shown in your pic)
A bad harmonic balancer will create negative harmonics through your crankshaft and that is what causes the crankshaft to break in a 6.5L

You can replace it from underneath the truck. Most auto parts stores have pullers you can rent to remove the balancer and pulley.

Here is some info from the 6.5L FAQ page that will help you.
How to install New harmonic balancer installed today..
  • Removal/Install Tools Here and Here
  • Tool For Stopping Engine Rotation While Removing/Installing Harmonic Balancer Click Here
 
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You can watch it from down there and it will look wobbly (sideways motion) as supposed to a nice rotation.

When doing replacement, replace the belt and a crankshaft seal behind the balancer for preventative maintenance.
 
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Discussion Starter · #6 ·
You can watch it from down there and it will look wobbly (sideways motion) as supposed to a nice rotation.

When doing replacement, replace the belt and a crankshaft seal behind the balancer for preventative maintenance.
Took a look down there and noticed that it spun normally, I'll take better look tomorrow with my camera and post it here. Regardless I ordered the harmonic balancer and pulley and hope to get it done soon from napa. Will be digging deeper in this forum to do as much preventative maintenance as possible, soon I won't have a steady flow of income and would hate to spend money on a new engine because of negligence.
 

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Discussion Starter · #7 ·
Here a video of the HB in motion. I'll be sending it to the shop tomorrow for the replacement. Do any of you hear any abnormal sounds in the video?
 

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Here a video of the HB in motion. I'll be sending it to the shop tomorrow for the replacement. Do any of you hear any abnormal sounds in the video?
I hear a light tap sound like a playing card in the spokes of a bicycle that could be associated with the HB...
When the shop does the work make sure they are replacing both the HB and Pulley.
Both contain rubber and both have been exposed to the leaking oil and have been on the crankshaft about the same time.. so if one needs replacing, they both do..
(y)
 
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Discussion Starter · #9 ·
I hear a light tap sound like a playing card in the spokes of a bicycle that could be associated with the HB...
When the shop does the work make sure they are replacing both the HB and Pulley.
Both contain rubber and both have been exposed to the leaking oil and have been on the crankshaft about the same time.. so if one needs replacing, they both do..
(y)
Sure thing, have both the new pulley and HB on hand. I made a list for the mechanic to go through, I'll provide down below incase you think I should add anything more to that list. I really do want this engine to last for maybe another 100k miles or more if possible and not have to take it back to the shop for an emergency situation so I want to do as much preventative maintenance as possible.


To Do List:
  • Harmonic Balancer and pulley replacement
  • Inspect any belts needed to be replaced
  • Inspect oil cooler lines (connections and clips, and check for potential leaks or loose connections)
  • Inspect cooling system
  • Repair A/C, and inspect for leaks or broken parts
  • Fix weird wobbling noise when turning and accelerating
  • Fix faint wobbling every few seconds from engine at idle
  • Dome and footwell light problems (suspected connector on driver side b pillar under carpet)
  • Any other suspected problems related to the engine
 

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Sure thing, have both the new pulley and HB on hand. I made a list for the mechanic to go through, I'll provide down below incase you think I should add anything more to that list. I really do want this engine to last for maybe another 100k miles or more if possible and not have to take it back to the shop for an emergency situation so I want to do as much preventative maintenance as possible.


To Do List:
  • Harmonic Balancer and pulley replacement
  • Inspect any belts needed to be replaced
  • Inspect oil cooler lines (connections and clips, and check for potential leaks or loose connections)
  • Inspect cooling system
  • Repair A/C, and inspect for leaks or broken parts
  • Fix weird wobbling noise when turning and accelerating
  • Fix faint wobbling every few seconds from engine at idle
  • Dome and footwell light problems (suspected connector on driver side b pillar under carpet)
  • Any other suspected problems related to the engine
On your next "upgrade" list you should really consider changing out those OEM oil cooler lines to stainless braided.
The OEM lines are just a ticking timebomb waiting to take out your engine.
Road vibration, corrosion from moisture/road salts or a combo of both will take the clip holding the lines against the block out of action when you least expect it..
 
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Discussion Starter · #11 ·
On your next "upgrade" list you should really consider changing out those OEM oil cooler lines to stainless braided.
The OEM lines are just a ticking timebomb waiting to take out your engine.
Road vibration, corrosion from moisture/road salts or a combo of both will take the clip holding the lines against the block out of action when you least expect it..
Sure will, I edited the list so that the mechanic wouldn't replace the lines if incase they do find the need to replace them. I definitely will schedule a day to get it replaced in the coming weeks with the stainless braided lines. Thanks so much for your help and advice, really do appreciate it!
 

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Discussion Starter · #12 ·
I will be posting another video after the repairs to see if that noise OkDually refers to and a couple other noises my truck does during acceleration goes away. I tried recording while driving and it's hard to pick up the noise I'm referring to but it's like a wobbling noise that kicks on and off when accelerating, sounds almost like a loud treadmill with a loud bearing when you accelerate on it and it can be a short .5 second or a long 3 second interval and almost always kicks in when accelerating outside of curbs. It happens constantly at slow to mid speeds but it drives perfectly. It's just a little sound so not alarming, but still not proper, coming from the engine since the noise accelerates with it. My truck was used for snow plowing so I don't know if the engine gets retrofitted with some equipment that could make some additional noise but notice the first picture there's another small pulley attached to the HB pulley with a Nascar belt which isn't on my dad's 2500 6.5 truck, don't know what's that for. And there's also a faint vibration that I can feel during idle, you really gotta stay still to feel it, it's faint but it vibrates a little bit every 5 seconds or so. Thanks for the help guys.
 

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notice the first picture there's another small pulley attached to the HB pulley with a Nascar belt which isn't on my dad's 2500 6.5 truck, don't know what's that for.
What's the belt attached to on top?
 

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Discussion Starter · #14 ·
What's the belt attached to on top?
It's attached to whatever this thing is, I don't know if it's like a hydraulic pump but there's two lines going to another thing on the other side of the engine shown in figure 2.

Figure 1:
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Figure 2:
641444
 

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Yes. It looks like a hydraulic pump and fluid reservoir. Most likely for a snow plow.
 

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X2^^ Hydraulic pump for the plow... If you are not planning on using the plow feature I would remove the pump, pulley and associated lines with the pump
 
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Remember to replace the crankshaft seal behind the HB while doing the Pulley replacement.
 

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Discussion Starter · #18 ·
I unfortunately didn't replace that seal because I couldn't find it at the auto parts store, I asked them (the mechanic) what the condition of the seal was, they told me it was OK. Here's a video of the new HB and pulley, if you still notice any abnormal sounds let me know please :D, the sounds I was referring to earlier didn't go away, so I assume and hope it's just the hydraulic pump making those sounds. I'll remove the equipment when I send the truck back to the shop, or I'll try to do it myself. In addition to that I now hear a short "beep" kind of noise every time I accelerate from 0 coming from the back, wonder what that could be. I'll also attach photos of the old HB and pulley for any future readers reading this thread, from what I can see they don't look too worn out, do they? I see one side of the pulley looks quite worn out (Figure 4).


Figure 1:
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Figure 2:
641468


Figure 3:
641469


Figure 4:
641470
 

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It is an old diesel truck, noisy should be normal.
It is not a Lexus or Toyota.
 
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I unfortunately didn't replace that seal because I couldn't find it at the auto parts store, I asked them (the mechanic) what the condition of the seal was, they told me it was OK. Here's a video of the new HB and pulley, if you still notice any abnormal sounds let me know please :D, the sounds I was referring to earlier didn't go away, so I assume and hope it's just the hydraulic pump making those sounds. I'll remove the equipment when I send the truck back to the shop, or I'll try to do it myself. In addition to that I now hear a short "beep" kind of noise every time I accelerate from 0 coming from the back, wonder what that could be. I'll also attach photos of the old HB and pulley for any future readers reading this thread, from what I can see they don't look too worn out, do they? I see one side of the pulley looks quite worn out (Figure 4).


Figure 1:
View attachment 641467

Figure 2:
View attachment 641468

Figure 3:
View attachment 641469

Figure 4:
View attachment 641470
Pics 1,2,4 show oil damage and tired rubber on the parts.
I don't hear the noise I heard before
 
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