[1996 Chevrolet Camaro RS V6 3.8L 2-door coupe, 198,000 miles]
Transmission rebuilt a few years ago and rear main seal subsequently replaced. A few months ago, took to mechanic due to leaks.
Practically all major components replaced recently, including water pump, transcoolant lines, catalytic converter, oxygen sensors, fuel injector, fuel pump, ignition coil, belts, including timing belt, spark plugs, fuel filter, air filter, etc.
Found oil leak and took back to mechanic. He kept the car for a week, but found nothing. Both engine oil and transmission fluid continued leaking. (Needed to add 2 qts. oil.)
A couple weeks later, check gauges light came on at stoplight and engine died. On way home, died several more times while idling at stops. (Engine had not been run too low on oil, as it was being continually monitored and topped off.)
Mechanic now says needs new rear main seal and possibly bearings in engine.
Engine making clacking noises and breaking down-seems to be a rod. Car not driveable.
(Contamination of oil by transmission fluid had been based upon extremely thin consistency of the oil and possible subtle discoloration).
The sudden severe problem despite the recent extensive overhaul is not making sense. Along with sloppy actions such as neglecting to tighten a nut on the oil pan (not just inadequate tightening, but barely threading it on) have called into question whether anything was inadvertently done by the mechanics that led the rear main seal to fail again already or other components that would account for the symptoms.
Need a vehicle, so this is the only opportunity to look into these concerns/possible recourse before the car is sold and unavailable.
Impressed by the knowledge and involvement of the Cartalk community. Thanks a lot for your advice.