If you have a car that leaks oil, then you know it's an annoyance and an environmental hazard. Most of the time, these leaks are small and cause few problems other than a stained driveway. However, even these small leaks may be a sign that something bigger could be happening either now or further down the road. Where are oil leaks likely to occur? Oil leaks are most likely to occur around the valve cover and the oil pan, but may also occur around seals, such as those in the front of the engine near the timing belt or chain.