Today we tear down a "bad" 6.0L LQ4 V8 Engine from a 2005 Yukon Denali. This came from a vehicle I purchased at a tow lot after it was abandoned. There is usually a reason why vehicles are abandoned and this one was quite clear once we got it started. At 252,000 miles there are so many variables as to what could be wrong with an engine, including the "quality" of the person's work who "fixed" it.
Why am I doing this? My name is Eric and I own Importapart. A full service auto dismantler. Part of our model includes dismantling blown up, failed and otherwise bad engines to salvage the good parts. We do not rebuild engines, merely supply parts to those who do!
TO BUY PARTS, visit www.Importapart.com OR email us at [email protected]
Every week I post one or more failed engine teardowns. Here are some of my past favorites:
2021 Explorer Police Interceptor 3.3L V6    • POLICE ENGINE BRUTALITY! '21 Explorer...  
2023 Nissan Rogue 1.5L 3cyl VCTurbo    • Nissan VCTURBO BAD ALREADY? 2021 Rog...  
Ford 351 5.8L Teardown    • LOCKED UP Ford 351W 5.8L V8 Engine Te...  
GM 3800 Series III, Is it actually bad?    • 'BAD' GM 3800 L26 V6 Engine Teardown....  

00:00 Intro
03:01 Turning the engine over, WELL TRYING TO
04:28 How do the spark plugs look? WE HAVE MALICE IN THE COMBUSTION PALACE!
06:20 Intake manifold off, How do the intake ports look? THERES "A" Problem!
07:03 Removing the LH Valve Cover, How was this engine maintained?
09:33 Cracking the LH Rocker arms loose, removing pushrods
10:22 Removing the LH Cylinder Head. First look at the bores!
12:55 Headgasket inspection.... Its starting to make sense!
14:41 Cracking the Rocker arms loose on the RH Cylinder Head
14:55 Pushrods are Mostly Good
15:44 Unbolting Cylinder head bolts and removing the RH Cylinder Head
16:24 MONEY SHOT!
17:00 How bad is the damage? Headgasket, piston and bore inspection
18:40 Science
18:56 Cylinder head inspection. DESTRUCTION
20:35 Water Pump Removal. I THINK WE HAVE OUR SMOKING GUN!
22:06 THE HACK MECHANIC'S DIRTY WORK
22:46 Harmonic Balancer Removal Attempt #1
23:42 Harmonic Balancer Removal Attempt #2
24:02 Harmonic Balancer Removal Attempt #3 OK FINE
24:32 Removing the front timing cover
25:21 Removing the Lifters & Trays, Inspecting the rollers #Allgood
26:42 Pulling the stock 6.0L Camshaft out of the block to Inspect!
28:40 Unbolting the pulling the oil pan
29:48 Removing the pickup & Windage tray, MORE PROBLEMS!
30:43 Oil Pump Removal, Disection and Inspection
31:52 Removing the first connecting rods and pistons from the crankshaft
34:17 Removing the last connecting rods and pistons
35:01 Unbolting and removing the main caps
35:33 Pulling the crankshaft out of the block
35:40 Full rotating assembly inspection. Bearings, Pistons, Rings, Rods, Crank, Journals, ITS ALL OUT
41:24 Removing a few valves from the "problem" cylinder head
43:18 Summary

I really hope you enjoyed this teardown. As always I love all of the comments, feedback and even the criticism. Catch you on the next one!

Eric