Auto Club South, Warning Signs, car maintenance and repairs. A puddle of oily fluid that is dark brown or black is probably engine oil. It could indicate a bad seal or gasket or a loose oil filter. A red oily spot is a sign of a transmission or power steering fluid leak. A puddle of clear water, especially after the vehicle has been left idling, is usually normal air-conditioning condensation.
Smells also are a strong clue to something amiss.
An odor like burned toast could signal an electrical problem. Have it checked immediately. A rotten egg or burning sulfur smell usually indicates a catalytic converter or emission control system problem. An acrid odor often means burning oil or oil leaking onto a hot engine part. Have it repaired quickly, or risk engine damage from low coolant.