I noticed today when i got to work that i heard some bubbling from the radiator. I went to look and it was spewing coolant out the overflow (i filled it up last night while doing some general maintenance). Even if it was overfilled it shoudln't be boiling. Could the thermostat i replaced five years ago be on its way out? It might not be opening enough and limiting the flow. When i am driving the temp gauge always stays below the halfway mark so i am thinking the cooling effects while driving are enough to keep the coolant from boiling over but when i park it has no cooling and therefore proceeds to boil over. I'm thinking it's either the thermostat or the fan clutch.
Any Ideas?
Any Ideas?