- Northstar engine problems: The Northstar engine used in the STS is known for several issues, including oil leaks, head gasket failures, and timing chain failures.
- Transmission problems: The 4T80E transmission used in the STS is also known for several issues, including slipping, flaring, and hard shifting.
- Suspension problems: The STS's suspension is known for several issues, including worn control arms, ball joints, and tie rod ends.
- Electrical problems: The STS's electrical system is known for several issues, including faulty ignition switches, window regulators, and door locks.
- Body problems: The STS's body is known for several issues, including rust, paint peeling, and chrome trim flaking.
It is important to note that these are just some of the common problems that can occur with the 1999 Cadillac STS. Not all vehicles will experience all of these problems, and some may experience problems that are not listed here. If you are considering purchasing a 1999 Cadillac STS, it is important to be aware of these potential problems so that you can make an informed decision.
