If you want to see what bearing fragments look like and what a spun bearing
can do to a motor, take a look at my website.
Look under MGB GT. Mine didn't give any warning, just a few metres down the
road and WHAM, the loudest banging I've heard from my MG. Result - Stuffed
Conrod, cracked Crankshaft and metal everywhere throughout the motor. Full
rebuild is necessary, and the block should be put in a hot tank and
thoroughly cleaned to remove any fragments. Also, if you have an oil cooler,
you should throw it away and replace. It's near impossible to get all the
metal out of there..
Best of luck, and if you tackle it yourself, then there's lot of people on
here to help out. Hopefully your noise isn't a spun bearing..