ever since i changed motors, the 370 seems to build up an assload of pressure in the overflow for the radiator. not sure why it does it, the 4.8 didnt ever do that. it probably gets 20-30 psi of pressure in there... when you unscrew the cap, you have to just be so gentle like a fizzed up coke. it will spray your *** every time, doesnt matter if it has been running 5 minutes or an hour.. same amount of pressure.

any ideas/suggestions ?

 

I'd say get a chemical block tester and check for CO gasses in the cooling system.

 

thats what happens when a head gasket is going out, IN SOME CASES

 

its been doing this for over a year now.

 

First guess would be combustion gasses, but if it's running fine and not losing any fluids (such as coolant), my gut tells me that we can rule that out. Could the vent/overflow hose that runs down be kinked or clogged? Maybe the cap is defective? If pressure builds up too much, eventually something's gonna blow...

 

True.. its a 16# cap, right?

 

I believe so, but I'm not 100% sure...