Duramax Diesels Forum Truck of the Week
Old 02-16-2017, 08:37 PM
Dually681 Dually681 is offline
Join Date: Feb 2017
Posts: 2
Default 08 duramax silverado lmm engine locked up after 6 mo rebuild.

So i went and pulled the motor. Thinking the worst.
Mains are good. Not locked there. Pistons rods and sleeves look good from bottom. Pull the glow plugs and injectors no hydro lock looks good there.
Shine light to cam. All looks clean up there.
Pull head covers and no dropped valves. Im stumped. Only thing i can think of is timing something broke ip front and locked the motor there. Really isnt anything else i can think of.
Any suggestions. This happen to anyone here before?
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Old 02-16-2017, 08:51 PM
minerigger's Avatar
minerigger minerigger is offline
Join Date: Dec 2013
Location: Casper, WY
Posts: 2,610

Shear a pin on the harmonic balancer?


Gauges, Danville Tunes, 5" Dumped, Trans by Evan, DP Stg2r, Sleeved/Braced and some other odds and ends crap that we all have

Last edited by minerigger; 02-16-2017 at 09:19 PM.
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Old 02-16-2017, 09:09 PM
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TheBac TheBac is offline
Why do I keep doing this?

Join Date: Apr 2008
Location: Mid Michigan
Posts: 11,446


What year engine? What was done to it? Running and suddenly stopped or what?
"BBT" -- 2003 GMC CC/SB 4x4 12.14@111.15
"Flyin' Brick" -- 1999 Chevy 1500 RC/SB 2wd -- stalled out, no motivation
"The Cruzer" -- 2014 Chevy Cruze Diesel -- the fun little DD
"The Bigger Boat" -- 2011 Workhorse P700 - 6.0LS/Allison - what I drive at work

Two wrongs dont make a right, but three rights do make a left.

Reality is a matter of perspective.

This forum isn't for the weak of heart.....or wallet.

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Old 02-16-2017, 10:02 PM
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2004LB7 2004LB7 is offline
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2008 Chevrolet 3500HD DRW LTZ
285/75/17 Nitto Dura Grapplers, 4.56 gears, Front and rear ARB lockers, Efi Live tuning by me, Raptor 160 LP, Cognito 4-6 NTB Lift, 4" Exhaust, Built Trans by Mike L.
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Old 02-17-2017, 05:22 AM
Dually681 Dually681 is offline
Join Date: Feb 2017
Posts: 2

Its an 08 LMM. Think its timing set that broke and locked up.
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Old 02-17-2017, 06:22 AM
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c20elephant c20elephant is offline
Join Date: Apr 2013
Location: Phoenix, Arizona
Posts: 2,065

I was out in Mesa yesterday at Copperhead Diesel (DangerDog on here) and his opinion on these trucks is people mis-diagnose these truck all too often and end up spending money and not fixing the problem.

I bought a LLY complete engine last year to part out, the guy I purchased it from stated his mechanic told him it was a blown engine due to an overheat situation. When I pulled the valve covers then started unbolting the rocker assemblies when I noticed several "loose" pushrods. These were bent and no evidence of a severe over heat as I was told. I sold the heads and when checked were in A-OK shape.

Not sure what to tell you Dually681 other than inspect the parts closely to find a mechanical failure otherwise it could have been an sensor issue or maybe what the other's had suggested.

BTW, what were the CEL codes prior to removal of the engine..?
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