hammering at idle?
12-12-2010, 12:58 AM
#1
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hammering at idle? We have a car that has a phantom hammering in the motor, towards the back. It makes all kinds of clanking noise at idle, but as soon as you give it throttle it goes away, then back at idle, she makes the noise some more. It has gobs of oil pressure, no power loss, no smoke. It will drive around just fine, was driven home an hour away when swapped for. Trans was pulled (I sounded like maybe clutch/flywheel issue) but everything checked out ok, and it still makes the noise with the trans out. It isnt a constant noise either, it varies in sound, kind of like shaking a can full of big rocks. I'm thinking piston skirt broke and piston moving around or wrist pin. any off hand ideas? It needs to come apart but its just not a noise i've ever heard from a ls motor
12-12-2010, 10:33 AM
#4
Had a similar experience with my cammed 6.0. The noise was half speed of crank rpm, so i took a mechanics stethoscope and place on each of the four bolts on the valve covers and the noise was coming from # 4 cylinder. After tearing it down found cam lobe and lifter wear for the # 4 valves.
12-12-2010, 02:42 PM
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Had a similar experience with my cammed 6.0. The noise was half speed of crank rpm, so i took a mechanics stethoscope and place on each of the four bolts on the valve covers and the noise was coming from # 4 cylinder. After tearing it down found cam lobe and lifter wear for the # 4 valves.
start checking valvetrain
