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Old 12-03-2007, 03:33 PM
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J-Ri J-Ri is offline
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Re: 02 Silverado, Wierd Knocking Sound

Sounds like a lifter for an exhaust valve is bleeding down. These engines use hydraulic lifters that use oil pressure. After sitting for a while, the pressure can bleed out, causing clicking in the valvetrain. After the engine has been running, it fills back up and the noise is gone until it sits again. If you're using a heavier oil, it can make it worse. I would use the thinnest oil your owners manual says you can use (probably 5w30). You may also want to try a crankcase cleaner and/or some Lucas oil stabilizer.
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'04 Cavalier coupe M/T 2.2 Ecotec
Supercharged 14 PSI boost, charge air cooler, 42# injectors
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Poly engine/trans/control arm bushings
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