Knocking sound out of nowhere

2000 PONTIAC GRAND PRIX
199,000 MILES
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WHITëBøI XâPøNë
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Car quit running all of a sudden. It was not running hot had oil, but heard bubbling noise waited a few hours started up making a knocking sound from top of engine.
Apr 18, 2017 at 12:57 AM
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HMAC300
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noises are hard for us to diagnose on here. pull a valve cover and see if you can see a broken or loosened rocker arm or broken spring something on that order if spring is broken valve may have dropped and hitting piston.
Apr 18, 2017 at 6:19 AM