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'97 5.7 Vortec bottom end knocking

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Old February 18th, 2023, 10:31 PM
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Default '97 5.7 Vortec bottom end knocking

I bought a '97 K1500 & as soon I finished the test drive & bought it a knocking started on the lower end of the engine. It almost goes away when I'm coasting and when the engine is all warmed up but it is worse when it is cold or accelerating hard. I'm looking for ideas of how to silence it or fix the problem. I appreciate any ideas & help
Old February 19th, 2023, 3:10 PM
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Remove the oil pan, find the loose connecting rod and determine if it’s the rod bearing or the wrist pin that’s causing the knock.

Replace the necessary parts unless the crankshaft has been damaged. If the crankshaft is damaged, plan for a rebuild or engine replacement.
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Old February 19th, 2023, 7:15 PM
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Cancel the cylinders one at a time. This takes the load off that cylinder. The one that changed the noise is the one to look at. Those engines would get piston slap and be loudest on cold start and go away at operating temp. Hope you find this helpful.
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Old February 23rd, 2023, 12:00 AM
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Thanks for the advice guys! Next oil change I will drop the pan & get it sorted out. I appreciate the help!
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