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Q: Engine Knock only during start up and acceluration, some oil found in spark plug well also. possible rod knock

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2007 Scion Tc Auto, I have a somewhat noticeble knock only during startup( less than 3 seconds during turning over) and during acceluration between 2k-3krpm. During idle it sounds completely normal no abnormal tapping only slight value tapping which is said to be normal in these cars. I notice some oil on my spark plug and in the well of cylinder 1 during tune up other three are dry. Also smokes a bit near the headers near the first value. Could this be sign of possible rod bearing failure, or spark knock? no CEL or oil level lights are on.

My car has 167000 miles.
My car has an automatic transmission.

A: Hi there: If you’ve found oil in the spark...

Hi there:

If you’ve found oil in the spark plug well is a sign of a fairly serious problem that should be inspected and repaired immediately. It is almost always due to a failing gasket or O-ring but can also be the result of a failing piston or worn valve guides. This could be the source of the engine knock and other issues you’re having. It’s probably a good idea to have a professional mechanic complete a oil is leaking into spark plug well inspection, so they can determine what’s causing your issues.

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