Hi Ho, I am afraid I know the answer...I have a Ford Ranger 4wd, 2000 120k. Ran well, great shape, reliable and quiet running. Oil pan leaked and I got tired of going under and used Devcon in attempts to stop leak..reoccurring issue. So I dropped the $500 to get new 0il pan. Started it up following morning after driving errands and home from shop and saw a cloud of smoke on start up never seen before, cleared away and didn't think about it again. Drive round trip for about 70 miles and while driving at slow speeds back in town, the oil gauge started pinging back and forth, and the knocking started. By the time I got home I do not dare to drive it anywhere as while the oil gauge does not fluctuate anymore the rapping has increased. What could have started this chain of events? Can I expect the garage to replace the engine? Vehicle is worth 4k replacing engine probably 3K..while a beautiful useful truck body sits in yard is it really worth it? Bad draw on the cards?