My car overheats after 10min of driving. I have to pull over until it cools off so I can drive. The car is parked at home now since this problem started. What could be the cause? I have a feeling it may be the thermostat. The block at the tip of my engine is really hot. I'm guessing no coolant is being pushed to the engine. Any ideas? It's a 1998 528i with 150k miles on it.