Sometimes there is no sign of a problem. I was replacing an oil pan gasket on my mom's caravan and when I pulled the pan I saw a chain hanging. Looked around, followed it and it was to the oil pump. The odd thing is the light functioned and the van drove normally. Just did have chunks of the sprocket and chain in the oil. To be safe I replaced the engine with a good used motor. I wonder how long it would have ran... LOL