Wilsons Sandbox

I have an A9, with 61,000 miles. I have a 50+ mile commute, one way. The past two days she has been running hot. Yada Yada Yada Yada Yada . . . Any ideas, similar situations, recomendations ? Thank for your help so far. Part Two This last weekend I replaced the cap, replaced the hose from rdiator to reservoir. Cleaned the systems best I could. Flushed and replaced with new coolant. Visually inspected for cracks, holes in the plumbing = none. Rode it into work today ran cool the entire 50+ miles. Looked at the coolant level at lunch once again below the core. A T wrote; A possible exhaust leak past the cylinder head. Cars and trucks will do the same thing. The tell tale sign: Foam at the top of the radiator. This will also cause excessive pressure which could push collant into the reservoir. The first time this presented itself, once I had pulled off the highway, I removed the cap while everything was still warm, it looked like suds. As I filled the radiator, the suds flowed out. Didn't stop until I got a steady stream of coolant. Ever since, I've waited for the engine to cool before checking the coolant. Wacha think crack in the head gasket?