One problem related to engine knocking noise has been reported for the 2006 Cadillac CTS. The most recently reported issues are listed below. Please also check out the statistics and reliability analysis of the 2006 Cadillac CTS based on all problems reported for the 2006 CTS.
I took my 2006 Cadillac Cts into a gm dealer for a recall. They also changed the oil. Ever since they changed the oil, my car has been burning an excessive amount of oil. I had to put a quart of oil or more about every 500 miles. I put in 1 1/2 quarts on a Wednesday and on a Monday my car began making a loud knocking sound in the engine. Gm will not listen to me and now my car probably needs a new motor. I have babied the car and this is not my fault. Oil is in the car at all times and it should not throw a rod with oil.