96 Lumina valve train noise


Old 08-06-04, 05:39 AM
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Unhappy 96 Lumina valve train noise

96 Chevy Lumina, 3.1 V6. 106k miles. Very loud valve train noise that changes pitch as rpm is increased. With stethiscope, hear noise best around thermostat housing. Inspected all rockers, look good. Checked all valve springs, none appear to be broken. All push rods are straight. Lifters apear to be good. Ruled out wrist pin issue by removing plug wires one at a time. Noise doesn't go away. Noise does decrease whe engine is warm. All lifters are pumping oil. Where do I go from here?? Welter5
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Old 08-08-04, 05:39 AM
Join Date: Apr 2002
Location: Pittsburgh,Pa
Posts: 2,417
Pull the cover off the torque convertor and see if the noise is still there.Then remove the convertor bolts and push it back towards the trans and see if the noise is still there.Then post back with your findings.
Old 08-08-04, 07:56 AM
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Join Date: Oct 2003
Location: Boynton Beach Florida
Posts: 2,207
Another possibility could be carbon build up. You could draw small amounts of water through the PCV or other vacuum hose to counter something like that.
If I'm remembering the right engine, I think I had a rocker shaft break on one of those before. Are you getting any misfire?
Old 08-08-04, 04:56 PM
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Found source

Turned out to be a lifter, number 6 exhaust. Engine has roller cam. While rolling the roller with your finger, you can feel a flat spot, but not everytime. As if there is a needle bearing missing. The cam lobe looked boarder line. I replaced the lifter. The tap is 100% better but still there under load. Should I plan on replacing the cam? Thank you for responding.

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