I flushed my coolent the other day and topped it off (temp was in the 80s). Last night I topped it off because the temp. lowered and coolent pressure decreased(temp was in the 60s). Now that the temp rose up to 80 again the pressure is higher and when i squeeze the upper main hose it is pretty tight. My question is how much pressure is too much pressure? should i release some coolent or will the excess pressure go into the overflow tank?

 

It doesn't matter what the outside temp is, the radiator cap maintains a constant 0.9bar/13psi in the cooling system by letting coolant flow in and out of the overflow reservoir as the coolant temp varies. You don't need to do anything except make sure you have a functioning pressure relief cap on the radiator.

Go read this...

http://auto.howstuffworks.com/cooling-system.htm