There is a Radiator shaped cap in the engine compartment, usually on the passenger side of the engine. When the engine is COLD take the cap off, pull on the metal tab you can see, this will remove the thermostat, top up the coolant. Replace Thermostat and cap when full.
Then remove cap at the radiator top up there and make sure the over fill bottle is full to the cold line.
The system may require one top up like this after filling the system, if it requires more than one it has a problem!
The radiator cap is critical in the Fiero system and should be replaced every couple years just in case. If it messes up you will have all sorts of weird problems.
Foam contains pockets of trapped air which prevents conduction.
overheating
Honeycombing - is pockets of air trapped during the mixing process. The air-pockets stay in the mixture while it hardens - leaving a weaker area where the honeycombing has occured.
materials such as fibreglass are good insulators because they contain pockets of trapped air. :)
formed when molten rocks called magma becomes trapped in small pockets . As these pockets of magma cools slowly underground, the magma becomes igneous rocks
Blown head gasket is a distinct possibility, unless you just flushed and changed the coolant. In that case it is trapped air escaping.
Vesicular igneous rock is formed when pockets of gas are trapped during rapid cooling of lava.
You are most likely low on coolant or if you have had a coolant change recently the problem is due to insufficient coolant within the system which is also results in having air trapped in the system. Check your coolant level in both the radiator and the overflow bottle. I also recommend that you follow the procedure for removing trapped air in the cooling system. It can be found as part of the coolant refill procedure, which can be found at http://home.earthlink.net/~vqfaq/.
Trapped - 1910 was released on: USA: 31 December 1910
Trapped - 1911 was released on: USA: 1 November 1911
Trapped - 1915 was released on: USA: 28 June 1915
Trapped - 1922 was released on: USA: 1 January 1922