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Discussion Starter #1
Okay, put aside the diesel jokes, this is not normal for this motor.

I've logged only about 4K on my LBZ since November. Just noticed today an inconsistent tick/tap coming from the lower part of the motor on the drivers side. I listened thru a long rod and didn't hear anything in the exhaust area but heard it more clearly when I put it on the block down low. You can definitely hear it thru the wheel well on the drivers side better than you can from the top of the motor. It's definitey inconsistent with no particular pattern and you cannot hear it when you rev the motor up. It's happening when the motor is fully warm and idling. Oil is up, clean and pressure is good. I have not beaten on the truck to break it in. Maybe I should...?
It's got the same tap as a small block with solid lifters that needs an adjustment on 1 lifter...
It's go me stumped.
Anyone experience anything like this. Is it something breaking in and will go away after some more miles?
Truck runs fine...
 

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Do a search for "typewriter" or "tick" and get ready to read alot. Many describe the noise as an old manual typewriter and is random. No one has reported a problem associated with this noise. Supposedly they all do it just that the dmax is quiet enough to hear it.
Takes a lickin and keeps on tickin.....

Edit:Found the problem....
I have not beaten on the truck to break it in.
Break it in like a red headed step child:D
 

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There has been a few threads about this sound. GM even has bulletins out on it. Called the type writer syndrome. Normal my lbz has 7000 miles on it and it started about 3000 miles ago.
 

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Discussion Starter #4
gmcya;1568813; said:
Do a search for "typewriter" or "tick" and get ready to read alot. Many describe the noise as an old manual typewriter and is random. No one has reported a problem associated with this noise. Supposedly they all do it just that the dmax is quiet enough to hear it.
Takes a lickin and keeps on tickin.....

Edit:Found the problem....
Break it in like a red headed step child:D
Okay,
I have seen something on the typewriter deal but thought it applied to something else. So, this ticking is one more thing I just have to get accustomed to....What's next?

Is this tick heard specifically thru the wheel well on the drivers side? I cannot hear it well from the top of the motor down or on the passenger side at all or will that be next?
 

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Heron;1568828; said:
Is this tick heard specifically thru the wheel well on the drivers side? I cannot hear it well from the top of the motor down or on the passenger side at all or will that be next?

Yes. If you keep searching, someone posted the GM bulletin and it explains the sound, what causes it, and where you can hear it from. Sorry but I still cant find the actual bulletin.
 

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I can't hear it at all from the driver seat with the straight 4" exhaust screaming and me hangin on for dear life at wot:confuzeld
 

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Discussion Starter #7
ibfarmerduramax;1568842; said:
Yes. If you keep searching, someone posted the GM bulletin and it explains the sound, what causes it, and where you can hear it from. Sorry but I still cant find the actual bulletin.

Yup, found it. Man do I feel dumb. So much written about it. I just thought after having it to the dealer 9 times it was somthing else I had to deal with.
 

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Here is a copy of the GM bulletin:

"A random ticking noise may be heard in some LB7/LBZ's with the engine running at idle speed and with the coolant warmed to a temperature of 70 degrees Celsius or above. An Irregular metallic ticking/clacking sound like random typing on a mechanical type writer, can be heard at the lower rear of the left front wheel house. Some customers may also hear the noise inside the cab as well. This irregular ticking/clacking sound can be heard between idle and 1500 rpm. Above 1500 rpm the sound goes away, but returns once the engine is operated within the idle and 1500 rpm speed range.
The sound is caused by the relationship created from the engine block, main bearing crank pin, bearing inser, and oil film which generates a vibration that resonates though the block and is heard as a metallic ticking noise. This noise is most audible on vehicles that have engine main bearing tolerances that are closer to the minimum main bearing clearance specification. All Duramax engines have this condition, however some are more audible than others. Tolerances between nonaudible ticking engines and audible ticking engines are differences in clearances measured in microns.
Isuzu advises that they have experienced this condition in other diesel engines they manufactured over the last 20 years. Other manufactures of diesel engines such as Hino, Mitsubishi and Nissan also report similar noises in their engines. The LB7/LBZ bearing manufacturer has investigated this noise in the LB7/LBZ and state that no reliability or durability concerns are due to this condition.
General Motors Noise Vibration and Harshness group and Isuzu of Japan Engineering have done extensive testing and agree that no reliability or durability of this engine is effected by this issue. GM engineering has run a ticking engine on a 1200 hour dynamometer durability test and has also agreed that the noise condition does not effect reliability or durability of the LB7/LBZ engine.
The noise is a normal operating characteristic of this engine, It has no short term or long term detrimental effects on the engine. Do not attempt repairs for this sound."
 

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Just think of it as your own personal secretary typing away, I kinda like it. I know it's a little unnerving at first but nothing to worry about when you have a 100K warranty.
 

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I have the same noise too, not too bad. As long as you do not hear inside the cab.
 

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Mine does it to, it reminds me of when you run a vehicle for a long time and then when you shut it off you here the ticking and crackling from the exhaust.But on the duramax you don`t here it when you shut off the engine or at least not mine.My dad is a service manager for the local chevy dealer and he said they have a complaint all the time about this.
 

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I have a 2004.5 LLY GMC with 118,000 and it does the same thing. Not necessarily at a regular time frame. It did it tonight coming back for the superbowl party about a 75 mile trip. Mine also does it just at idle.
 

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Darn cool I saw this thread. Mine does it too and it only has 300 miles! I heard it yesterday when I was sitting in the Dunkin Donuts drive-thru waiting for the best coffee in the world! Anyway, I could not hear it at a stop light or anywhere else unless I got out of the truck and stood next to it or was next to a building with the window down so the sound could deflect off.
 

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Mine didn't start until I had around 4200 miles on her. From what I've read, many other guys didn't have any problems either til around 4000 miles. Has anyone else noticed this trend? Just glad to see that I'm not the only one with this problem. I was afraid my injectors were going SOUTH again:eek: Thank goodness for this site...now I can sleep again at night:rolleyes:

P.S. I definitely noticed that it got much louder after changing the oil. Using Rotella-T.
 

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glad to see this was at the top of the list tonight i havnt had much time to research this in the last couple of days, i just started experiencing this sound after i switched my entire fluids over to amsoil. i was kicking my self in the a** because i thought it might have had something to do with it. from what some of you say mine seems to be really louder than that, i have a remote start and while walking up to it in a parking lot i can hear it from probably 150 ft away. hope its alll good cause i have to much stuff to take off before i can take it to the stealer.
 

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Wow, glad i too read this thread as it was driving me crazy. I thought i had a cracked flexplate or something wrong. I too can hear it at idle from at least 50 ft away at times but most noticeable at a drive through in gear at idle warm. Guess i dont need to worry about that anymore though from the sounds of it.....its normal i guess. I have about 20,000 miles on it and its done since i can remember.
 

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Heard mine for the first time yesterday, walked past the truck when running and heard it. Scared me at first but remembered this post, it's all good.Truck has 7,500 miles on her.
 

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My truck has almost 3,100 miles on it, and you could hear the metallic ticking. It actually doesn't really bother me.
 
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