Engine Clicking And Tapping Noises problems of the 2003 Cadillac CTS

Car engine failed at 30,000 miles - it started making a clicking sound, so my husband decided to take it to the shop. He didn't even make it to the shop - just had to tow it. The car was driven gingerly by my 80 year old grandmother for 7,000 miles, then by me (age 40 with two children in car seats) for the remaining miles. Cadillac offered to pay 1/2 the cost to rebuild, but the total cost was estimated at over $15,000. They said there weren't any new engines to drop in, but they found one used engine (with 1 mile on it) that they could use that would cost about $4,150. However, they wouldn't pay any of the cost of dropping in the used engine. We opted to replace the engine at our cost instead so we could get away with paying $4,150 instead of $7,500. I complained to gm service department, and kept being given incorrect information. One person would tell me they would pay 1/2 the cost to repair or replace the engine, the next would say they would not pay. I kept good records of all persons contacted during the long, long process. They even had me gather all my prior service records so they could be certain the car) had been properly maintained (which it had. ) at one point I was even told (by the district specialist office at gm) that my grandmother had apparently purchased an extended warranty on it, and they could just use that. Later, I was told that no extended warranty existed. I was led on and misinformed for 1 1/2 months, while my car sat at the dealership 90 miles away. I was without my vehicle for 1 1/2 months, while everyone decided what should be done, and as it ends up, it could have been done immediately if I hadn't been given the run around being told gm was going to help with the repair cost. Not a good experience - not a good car.