My 2005 STS Norstar V-8 since it was new. Currently it has almost 80,000 miles. There were a few minor mechanical problems when new, all covered under warranty, but over the last several years the repairs have been minimal, or just routine maintenance. The car has very good handling, braking and acceleration for a luxury car, and plenty of room to ride very comfortably, which makes road trips no problem. With the Norstar V-8 it has plenty of power, but without sounding like a "boy racer."
I loved the look and smooth ride. I bought my STS with 7K miles, certified pre-owned with extended warranty. At 18k miles the fuel pump went then 33K miles the water pump went after that it was something BIG each year. Cat converter replaced, intake position sensors, replaced vent solenoid, motor mounts, right & left lower control arms just to list a few. (seriously!) Transmission started clunking especially while driving slow or going from reverse to drive. Always garaged and maintained, I had to stop the $ bleeding at 85,000 miles when the transmission/drive train was about to drop out. The Cadillac dealer said new drive train $3,500 and there would be possible other issues. I'm done with Cadillac, this was my third, my beautiful Eldarado had mechanical troubles as well. Too bad, they were such beautiful LOOKING cars. Perhaps it is the aluminum North Star engine? Since my experience I have heard of others having numerous problems with this system.
Owned the 2000 STS, 2001 STS, 2002 STS, 2003 STS and now the 05 STS. The interior is shameful compared to the 98-04 STS. The exterior however is marvelous particular the front and back end. Lots of standard features love the power of the V8 N*. Heard the V6 was no good :(
In 2005 I leased my 5th (and final) one. I love the car. Comfortable, powerful and classy. But sad to say, Cadillac decided to discontinue the model. I have been driving these cars (SLS and STS)for over 15 years and never had any major problems. Except for normal wear of consumables. My 2005 has never had to be tuned, and continues to run like a dream. That's reliability.
AWESOME Bose 15 speaker sound system! Northstar V-8 power, heated/cooled seats, great looking leather & wood interior. Just a class car.
the ONLY negative is the lack of storage space. Glove compartment is insufficient, center console is small and any cd's use up most of the space.