To properly fill a Fiero cooling system (or "burp" it.)
Raise the rear of the car.
Remove the front and rear filling caps. Pull the thermostat out.
Pour premixed coolant into the rear cap until the radiator is full. ((Filling from the back helps push air bubbles out of the coolant pipes under the car.))
Cap the radiator when it is full.
Fill the coolant thank to the "add" mark with the same mix you are using in the rest of the system. Remember the tank says check hot... We want to leave room in there for coolant to expand out of the radiator.
Fill the engine until you reach the top of the hose connected to the thermostat housing.
Start the car and let it run with the thermostat cap off. This will burp out the big air bubbles. Leave the car running. (Some cars hate having the cap off. I don't know why. If yours is like that then just put it on. Just don't let the thing warm up and build pressure. You only need it to run a minute or two. You may have to stop and check it several times. )
Pour in more coolant mix if the level drops below the top of the hose.
Once the engine stops spitting up air put the cap on.
Run the car to normal operating temp. This will happen fairly quickly unless the fan is on.
Let it run a few minutes. Keep an eye on the temperature to make sure you don't over heat. If you have an ECM
scanner hook it up for this. Watch the coolant sensor. If it warms up then drops, or fails to warm up, shut off the car. You likely have a big air bubble in the thermostat neck. (This shouldn't happen but it's something to watch out for. Gives you one more thing to use your
scanner for.)
Shut it off and let it cool.
Open only the rear cap to check the system and top it off.
Install the thermostat now and cap the system.
Run the car to operating temp
Check the overflow tank. Fill it to the full line.
Shut off and let it cool. Then lower car.
Check the level in the engine again. It should not need more than a little bit if any.
