Misfire timing chain broke?

2008 BUICK ENCLAVE
180,000 MILES • 3.6L • V6 • 2WD • AUTOMATIC
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JOEGOODMAN25
Misfired timing chain broke replaced chain still misfire with new coils
Apr 27, 2026 at 7:18 AM
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STEVE W.
  • ASE Certified Mechanic
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  • ASE Certified Mechanic
What code(s) are you seeing? You say it misfired and broke the chain. Do you know what cylinder misfired?

If the chain broke while it was running you might have had a piston tap a valve enough to bend it. While the engine is considered a non interference engine I have seen them hit more than once. GM issued a a couple service bulletins on them because of the timing issue.
These will take you to them.
https://static.nhtsa.gov/odi/tsbs/2015/MC-10113723-9999.pdf
https://static.nhtsa.gov/odi/tsbs/2014/MC-10111996-9999.pdf

You say you replaced the chain, did you have the updated parts and tensioner as well as these 2 updates? If yes then I would do a leak down test just to see if it's valve related.

Apr 28, 2026 at 1:27 AM
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STRAILER
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Please let us know.
Apr 29, 2026 at 5:47 PM
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