Oil leak top rear of engine?

2012 GMC SIERRA
300,000 MILES • 5.3L • V8 • 4WD • AUTOMATIC
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DGGJR
  • MEMBER
  • 1 POST
Removed whole top end as well as the valley cover for dod put back together had massive oil leak seams to be top rear of engine
Aug 26, 2025 at 8:08 PM
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MECHTRIX
  • AUTOMOTIVE REPAIR CONTRIBUTOR
  • 382 POSTS
Did it leak there before the work was done ? sounds to me like its leaking in the same place again in the valley between the block and down below the intake manifold or near the rear portion of the cylinder head but wherever it is you can know until you see it with your own eyes so"
Id get a mechanics mirror and a strong light to see if you can spot it you can also use a scope woth an end light to get in there and look at it with that too ..
you might have to pull it off again hopfully not good luck hope this helps.
Aug 26, 2025 at 10:50 PM
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STRAILER
  • AUTOMOTIVE REPAIR CONTRIBUTOR
  • 54,178 POSTS
There is an oil pressure plug at the rear of the engine, it maybe leaking. Please go over this guide to help

https://www.2carpros.com/articles/engine-is-leaking-oil

Please upload pictures or videos in your response of any problems.
Sep 5, 2025 at 9:27 AM