Some Cadillac Seville owners report experiencing significant oil leaks from the rear main seal, often starting as slow leaks that can lead to puddling of oil in the driveway. This leakage may pool on the bell housing of the engine and transmission, indicating a more serious issue. Repairing a rear main seal leak is commonly described as labor-intensive and expensive, with costs at a Cadillac dealer potentially reaching around $2000 due to the complexity of separating the engine and transmission. Additionally, some owners find that rear main seal leaks can occur alongside leaks from the oil pan gasket and transmission pan gaskets. For those considering a DIY repair, it involves extensive steps such as removing the exhaust and oil pan to access the rear main seal. Promptly addressing this issue is crucial to prevent further oil loss and potential engine damage, and consulting a mechanic or Cadillac dealer is advisable for effective resolution.

Some Cadillac Seville owners report experiencing hard starting issues that require multiple key turns to start the vehicle. Common causes include a weak battery that may not provide sufficient power, leading to difficulties in starting. Additionally, worn starters that draw too much current can also contribute to these problems, often necessitating replacement. Owners have noted that worn or corroded battery cables can impede electrical flow, making inspection and replacement of damaged cables essential. Issues with the fuel system, such as a faulty fuel pump or clogged fuel filter, can further complicate starting efforts, highlighting the need for proper fuel system function. Furthermore, problems with the ignition system, including the ignition switch or components, can cause starting difficulties, suggesting that checking and replacing faulty parts may improve performance. Some owners recommend checking for diagnostic trouble codes (DTCs) using a quality code reader to identify specific issues affecting the starting system. Regular maintenance, including cleaning or replacing spark plugs and ensuring a proper engine tune-up, is also advised to enhance starting reliability and overall vehicle performance.