Spun bearing??

Got a 86 G54. Always ran great. One very cold morning started and ran for about 5 secs. and then something happened. Started a deep squeal and some sort of mechanical resistance became apparent. Thought it was spun bearing and pulled pan. No metal but odd pieces of hard plastic or gasket present. Also looks like some valve cover silicone. What could be the cause other than a bearing? Runs fine although I have stopped driving it. Thanks

Timing chain tensioner?

+1 on that. If the plastic looks like black strips/fragments, more than likely the timing chain has blown through a guide or the chain tensioner has died. Only way to tell is pull the timing cover and water pump off. If they have given up you'll need a complete chain and guide kit.