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*****UPDATE*****
Resolved... I found an additional fastener I had missed that was recessed and difficult to visualize. After removing this last fastener, the timing chain cover came off just fine...
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In the middle of a teardown on my 2012 Toyota Tundra, 1UR-FE engine, 4.6-liter, V8 (150,000 miles). I suspect a blown head gasket in bank 1 (driver's side). Sudden loss of power and oil pressure drop to zero while driving on the freeway (running perfectly before). Now misfires in 1, 5, 7, some engine knocking. Leak-down test supports blown head gasket: Cylinders 1 (70%), 3 (35%), 5 (65%), 7 (55%). Bank 2 is fine. Emissions pass on Innova scan (no smoke). Significant air escaping into intake manifold from cylinder 1. Also multiple spark plugs fouled with oil (mostly in Bank 1), likely from bad tube seals (may also be contributing to misfiring).
Teardown to remove head (and rebuild as needed) was going well. Valve covers removed and strip down to remove timing cover completed. All timing cover fasteners removed (verified this at least 5 times now with the repair manual fastener diagram). I have pried the timing cover about 1/4" most of the way around, but it remains sucked down just at the apex of bank 1 (the area marked in "red" in the picture).
I have no movement at all after 2 hours of prying in that area. It feels like I missed a fastener there, but--according to the manual--I have removed all the timing cover fasteners.
I'd be most grateful for suggestions and insights...
Thank you!
Resolved... I found an additional fastener I had missed that was recessed and difficult to visualize. After removing this last fastener, the timing chain cover came off just fine...
****************************************************************************************
In the middle of a teardown on my 2012 Toyota Tundra, 1UR-FE engine, 4.6-liter, V8 (150,000 miles). I suspect a blown head gasket in bank 1 (driver's side). Sudden loss of power and oil pressure drop to zero while driving on the freeway (running perfectly before). Now misfires in 1, 5, 7, some engine knocking. Leak-down test supports blown head gasket: Cylinders 1 (70%), 3 (35%), 5 (65%), 7 (55%). Bank 2 is fine. Emissions pass on Innova scan (no smoke). Significant air escaping into intake manifold from cylinder 1. Also multiple spark plugs fouled with oil (mostly in Bank 1), likely from bad tube seals (may also be contributing to misfiring).
Teardown to remove head (and rebuild as needed) was going well. Valve covers removed and strip down to remove timing cover completed. All timing cover fasteners removed (verified this at least 5 times now with the repair manual fastener diagram). I have pried the timing cover about 1/4" most of the way around, but it remains sucked down just at the apex of bank 1 (the area marked in "red" in the picture).
I have no movement at all after 2 hours of prying in that area. It feels like I missed a fastener there, but--according to the manual--I have removed all the timing cover fasteners.
I'd be most grateful for suggestions and insights...
Thank you!
