1998 Chevy Lumina Engine Scratching

1998 CHEVROLET LUMINA
165,000 MILES • 6 CYL • FWD • AUTOMATIC
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MAD KING
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Hello,

it is nothing sirious, I hope, but when I give some speed the engine sounds like it is scratching or better rattling. I thought first maybe a loose exhaust clamp, but it isnt.

Does anyone have any idea what this can be and how I can fix it. It is annoying.

Thank you
Sep 7, 2010 at 6:44 PM
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MMPRINCE4000
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Rattling is normally pre-ignition, or fuel/air mixture ignites prematurely.


Try a tank of high octane gas, see if pinging goes away.

If it does this all the time, you can damage engine.
Sep 11, 2010 at 8:57 AM
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MAD KING
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Thank you for your answer, but it doesn't sound that it is coming from the injection, but more from the exhaust manifold.
The pinging would be coming more from the intake/outlet valves, tight?
Sep 11, 2010 at 9:15 AM
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MMPRINCE4000
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Pinging comes from piston, sounds like hitting a ball-peen hammer on a vice.

You may simply have an exhaust leak which can sound like a ticking noise.
Sep 13, 2010 at 10:11 PM
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MAD KING
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Thank you. Can it come from the EGR?
Sep 14, 2010 at 8:39 AM
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MMPRINCE4000
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EGR leaks can cause it, the EGR meters exhaust gasses into intake to reduce NOX emmissions.

Too little flow will cause engine to run a little hot, too much will cause it to lose power and stall.
Sep 14, 2010 at 9:27 AM
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MAD KING
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Thank you. I will check this out.
Sep 14, 2010 at 9:29 AM
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MMPRINCE4000
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Thanks for donation, and keep us informed.
Sep 15, 2010 at 7:32 AM
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