HELPPP!!!!??? Engine Cooling Problem.

[PlayersExpress]

Hey guys, this is somewhat scaring me and before I bring it into the stealership I want to see if i can fix the problem myself.

Background: Last summer my car blew the "transcoolant valve" (regulates the flow of coolant into and out of the engine. It was towed to The Porsche Exchange in Highland Park, IL. They fixed it and pressure checked the system blowing my water pump... total bill cost me $1700+ $200 towing.


Now: The engine goes from average running temperature then goes up into the redline above 250 degrees... and will come back down if i turn the Heater on full blast. The cooling fan is running at full blast constantly saying the system is overheating and it is blowing out some coolant here and there because it is so hot... but its not staying in the redline, the temp will drop from red to under the 2nd white line to normal temps then back up.. and down... Now on the expressway for the most part it was stayin within Normal operation except for one or 2 times in a 30 mile round trip on the expressway.


Any clue as to what it might be? I dont want to blow the engine (143k miles on it) and I dont want to drop another $2k into the cooling system that has been recently worked on and replaced. Ohh btw, all my fluids are fine. Oil, gas, and coolant.

Thanks,

Adam