Direct cause of my low compression?

Tiny
RYDER1477
  • MEMBER
  • 2004 CHEVROLET IMPALA
  • 3.8L
  • V6
  • 2WD
  • AUTOMATIC
  • 190,000 MILES
After replacing everything easily accessible that could have been related or direct cause of my low compression, loud operating, horrible fuel mileage issues, it has been confirmed the rear exhaust manifold gasket needs to be replaced. So, I was curious if there was an easier way to do it besides taking everything I just put on or replaced just to get to it.
Thursday, July 3rd, 2025 AT 9:12 AM

1 Reply

Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 52,185 POSTS
Low compression cannot be caused by the exhaust manifold, FYI. Can you upload a video of the engine so I can hear it? To me it sounds like you have a timing chain issue. This will cause the noises and other problems you have described. Please go over this guide as well:

https://www.2carpros.com/articles/the-reasons-for-low-compression

Please go over this guide and get back to us.

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Friday, July 4th, 2025 AT 5:08 PM

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