As of 2016, common problems with Cadillac engines include oil leaks from the lower crankcase portion of the engine blocks of 3.5-liter V6, 4.6-liter V8 and 4.9-liter V8 engines, and leaking head gaskets causing engines to overheat in Cadillac DeVilles. Cars manufactured in model years 1990 and 1993 to 2005 are affected. Other problems include excessive engine oil consumption.
To repair the oil leak properly, mechanics must remove the engine from the Cadillac. Drivers have reported the problem in Cadillac DeVilles they have driven between 9,400 and 235,000 miles.
Engine overheating can expand the cylinder head, strain the head bolts and damage the engine block threads. A blown head gasket often results. Before reinstalling the cylinder head, mechanics must repair the engine block threads. The defect causing the engine to overheat affects 4.6-liter V8 and 4.9-liter V8 engines in Cadillacs manufactured in model years 1993 to 2005. DeVille owners report experiencing the problem in cars they have driven between 17,400 and 298,354 miles.
Cadillac retired the Northstar V8 engine in the summer of 2010, after 17 years of manufacturing and installing the overhead-cam engines in its vehicles. The automaker introduced the Northstar in the 1993 Cadillac Allante, with the engine delivering 295 horsepower and 290 pound-feet of torque. The 4.6-liter V8 engine produced 320 horsepower in the Cadillac STS and SRX.