Alright gang... I am having a very interesting issue and would love to hear some ideas. My car is pushing coolant out of the overflow tank (one that is much bigger than the FF one) after a WOT run. Here are some details:

- The car does not run hot
- When the car cools, coolant in the overflow does NOT get sucked back in to the radiator
- I did a pressure test at 15 llbs and it held pressure
- My radiator cap seems to have a good seal. I can feel the tension when putting it on and I can see the indentation in the rubber seal from the filler neck.
- Dip stick shows no sign of coolant in oil

My two theories:

1. I have an air bubble hiding somewhere.

2. I have a failure in a head gasket that is small enough where it only rears its head during high load situations. The combustion gasses leak into the cooling system which causes too much pressure and it to puke out the overflow. The combustion gasses are higher pressure than the cooling system, no coolant makes it into the cylinder.

Thoughts? Answers?

Much appreciated!