LLY: Well there's your problem.....

duramaxnate

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Feb 18, 2014
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So I got an LLY engine from a friend that needs to have the headgaskets REDONE. Truck was originally leaking externally on the passenger side.

So long story short, he did the job, put everything back together and started up the truck, now its leaking on the passenger side. Ok, thinking worst case scenario here, heads could be warped slightly or other factors. He yanks it out, (its actually in an H1).
I tear it apart to get the heads over to the machine shop, and this is what i found.

Spot the problem...

Should hear back about the heads next week. They measured out ok (per GM's method but, not always a 100%)

Now cleaning everything up and prepping for reassembly.

PICS IN NEXT POST
 

duramaxnate

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Feb 18, 2014
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Pics
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2004LB7

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Dec 15, 2010
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One stud upside down or is the hex slot just filled with assembly lube?

Only other thing I can think I see is inconsistent amount of stud sticking past the nut. Maybe some not torqued?
 
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duramaxnate

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Feb 18, 2014
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One stud upside down or is the hex slot just filled with assembly lube?

Only other thing I can think I see is inconsistent amount of stud sticking past the nut. Maybe some not torqued?

The excess amount of thread sticking out was the major issue. When I pulled the driver's side off one part of the hg was soaked in oil and coolant. and that one I was able to pull out with my finger.

Everything else looks good.
 

DAVe3283

Heavy & Slow
Sep 3, 2009
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I did ARP studs on my truck back when the motor was stock. Drove it a couple years, then had a glow plug go through the #1 cylinder, so I tore it down. One of the ARP studs had backed out of the block all the way until it hit the valve cover.

I had done those studs using ARP assembly lube, per their directions. Ever since, I put the studs in dry with a drop of blue Locktite. Never had one back out since.

Anyway, the point is, I wonder if the studs weren't installed right, or if they backed out after a few miles? Especially with how much ARP lube appears to be slathered on everything in there.
 

2004LB7

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Dec 15, 2010
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"Technically" the studs need to be retorqued after a hundred miles or so

Not required by ARP, or at least not in their instructions. But I've heard many needing to do it at least once as the studs loosened up after a couple of heat cycles
 

duramaxnate

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These were not installed correctly. My buddy told me he didn't put them in all the way because he didn't think they needed to be.. . The head gasket was soaked with oil and coolant between the layers when I tore it down.

I've never had arps back out on any of the engines I've done, but have heard of it happening.

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PureHybrid

Isuzu Shakes IT
Feb 15, 2012
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I was thinking ARP called for a retorque if you DIDN'T use the ARP lube. But this was back when they also had a different initial torque sequence.

Good info here
 

duramaxnate

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Feb 18, 2014
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I was thinking ARP called for a retorque if you DIDN'T use the ARP lube. But this was back when they also had a different initial torque sequence.

Good info here

If I remember correctly, they made you retorque them back when the spec was only 95ft lbs right?

ARP doesn't now but I think they did when they first came out for these...
I could be wrong though, its been forever.
 

Ne-max

I like turtles
Nov 15, 2011
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If it's a high hp build I can maybe see the need to retorque. Even at that I don't believe its needed. Especially for labor involved. If your head and gasket are moving that much you have bigger issues going on. We do a couple duramax head gasket jobs a month. Never had a issue.
 

duramaxnate

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Feb 18, 2014
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I have heard of cases where one or two studs have backed out BUT, there was a warped head in the equation. Was that the cause? hard to tell for sure but most likely.

But I haven't really experienced that issue here when I was doing them.