hey guys, i need some clarification. what is the correct way to flush the cooling system, because my 85 GT has been over heating and i replaced the electric fan switch on the motor and the thermostat, but now its acting like its got an air bublle in the lines somewhere. i attempted to flush the system the way i thought it was done, but evidentally i was wrong >.<
May 19th, 2008
Posts: 743 From: Nevada, Iowa, United States Registered: Dec 2005
Well to properly "flush" a cooling system you need to take the block plugs out and flush the block, I've never flushed a Fiero however. It sounds like something bigger to me like the impeller is spun off the pump shaft or something. I'm just throwing that out there, someone will disagree with me.
Posts: 10007 From: Marion Ohio Registered: Apr 2004
Crank the heat up and turn the fan on next time. If you get heat out of the heater, then you have coolant flowing. If its cold, then you have a no flow situation. Either an air bubble or the water pump isnt turning.
Best way I found to burp them.
Fill from the front first, once its full, then cap it and fill from the back thermostat housing. When that comes up, go back to the front and just crack the cap until coolant rushes out. If you dont do this, there will be an air pocket there.
Then go back to the back and top off the thermostat housing. Do not put the thermostat in yet, wait until its working right (not overheating) to do that. By leaving the thermostat out, it makes the coolant flow from first start, and helps air gather at the thermostat housing instead of circulating through the system.
So top it off, and start the engine. Some cars you can leave the fill cap off and run the engine, just adding coolant as the engine runs. Im pretty sure the fiero will spew coolant if you do this, but you might try. What you would typically do is leave the cap off as the car heats up, adding coolant if it goes down. As the car comes up to tempature, the coolant will expand, and it will start running out. This is when you put the cap on, and take it for a drive. Then come back, let it cool, and top it off one last time.
If the Fiero sprays coolant when its idling with the thermostat cap off, thermostat out (it may or may not, I dont remember) then just fill it, start the engine for a few minutes, then turn it off and carefully remove the cap. It should not have gotten hot or built pressure, but be careful in case. Then top it off, start it and let it idle a little longer, continue this until it no longer needs topped off. Then take it for a drive, up to operating tempature. This will take a while without the thermostat in there. Bring it back home and park it until it cools. Once cool, top off the coolant and put the thermostat back in it.