cylinder knock only when warmed and idling


Old 05-01-14, 02:57 PM
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Join Date: Sep 2012
Location: The States
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cylinder knock only when warmed and idling

Hey guys good afternoon. Our 2001 dodge intrepid has developed lots of issues and one of the problems is a knocking in cyl 4 I think. It starts nocking 10 minutes after the engine starts. Once it occurs if you rev it up then it stops.
Now before this happened the oil light came on and my girl put more oil but over filled it by a quart. 2 days later it starts to knock.
Due to lack of work or lack of work completely, if I can't fix it then its scrap metal.
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Old 05-01-14, 03:12 PM
Join Date: May 2006
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Change the oil to 10W/30 with one quart of Lucas Oil Conditioner.

The overfill didn't cause it.
Old 05-01-14, 04:51 PM
Join Date: Apr 2014
Posts: 115
What you describe is fairly typical of a loose piston pin. Many people continue to drive their vehicles with loose piston pins for many miles without further trouble (besides the noise). If it where me, I'd probably follow Marbobj's advice and just drive it.

Usually engines that knock while above idle, and/or under load, are far more worrisome than those that only knock at idle.
Old 05-01-14, 04:55 PM
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Knocking or tapping? Tapping would be more up in the cylinder heads...knocking down in the block. A mechanics stethoscope will tell you.
Old 05-01-14, 06:16 PM
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I used my home made stethoscope and when I rev, even though the knock goes away I can hear rattling inside the cyl block. When I get some spare money I'll put in some different oil
Old 05-01-14, 08:52 PM
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Join Date: Mar 2010
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You likely busted connecting rod bearing. Now it taps and tap goes away under load, as rod is pressed into it. Think. Metal expands when hot, right? So rod bearing journal and bearing yoke on it expand a little, opening bearing journal. That increases bearing clearance and rod starts tapping. That happened when you ran low on oil.
Old 05-02-14, 11:29 AM
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I think I'll send it to the junk yard. One of the bigger issues it has is the trans kicking in and out in every gear. You can peddle to the metal but as soon as you lift off the throttle slightly, it slips out. To bad nice looking car too..

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