I was driving down the freeway the other day and I heard a ticking sound. I thought it was a water pump as there was water dripping so turned the car around and started to head home and the engine died. my first thought was oh crap what broke, nothing is overheating oil pressure was good what the heck. I tried to start it and all I got was a click of the starter. I put a socket on the crankshaft and it wouldn't turn clockwise so I turned it CCW and something fell out into the pan. got the car home and took the pan off and found a rod cap sitting in the oil pan and the bearing sitting on top of the oil pickup. no harm as far as I can see the crank or the engine so can I replace just that piston assembly or should I go for a full rebuild. it never burned any oil or made any noise until this happened. it is going to be an experiment, and I only paid 400 bucks for the car and everything else works on it including the factory security system in the center console

 

Find out why the cap came off. Loose bolts, spun bearing? Examine the bearing for possible issues. Check oil pump screen for metal and cut open filter to check for same.

Inspect the other caps and their nuts to make sure they are torqued.

Check that pistons valves for damage in case the piston, now free, hit them. Plus the balance shaft gears in case something fell from above and jammed between them.

The cost of full rebuild adds up fast. Its typically cheaper to obtain a used engine.

Suggest pulling the head and inspecting valves, cylinder bore, cranks, etc. If all OK, price the needed parts on the internet. Try Rockauto, Partsgeek , etc.

Compare cost to Craigslist cars being parted (engine) and auto salvage yards.