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Q: Changed timing chain guide and tensioner. Now car starts good sounds good until warm them starts to make loud knocking. 2004 Nissan Maxima

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Why would it knock only when warm. Any suggestions what it could be. Thanks

My car has 130000 miles.
My car has an automatic transmission.

A: Hello - the most common cause of engine kno...

Hello - the most common cause of engine knock when the engine is warm, is worn connecting rod or crankshaft bearings. Hot engine oil provides less "cushion" for these moving surfaces, which results in a hard knocking sound. If the engine knock is new following the timing chain tensioner, it is possible the tensioner repair was not done correctly. The tensioner use engine oil pressure as well, and if a tensioner was incorrectly installed and leaks oil pressure, bearing knock in other parts of the engine could result. I would recommend an inspection of the engine by a mobile, professional mechanic, such as one from YourMechanic, who will come to your location, diagnose this problem, give you an accurate assessment of damage and cost estimate for repairs.

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