cooling system startup air bleeding
Thread Starter
Teching In
Joined: Nov 2008
Posts: 11
Likes: 0
From: North Texas
cooling system startup air bleeding I'm just now starting up my 5.3 transplanted engine (which has been dormant and totally empty of coolant for years) into an older vehicle and upon the initial running the cooling system doesn't appear to be circulating the coolant. We've got a new radiator ,thermostat and hoses. coolant appears to be flowing thru the heater hoses fine. Because we've learned about the "steam vents", if not routed to the upper radiator hose area would tend to keep air inside the head cavity's to some extent, we've routed that small hose coming thru our throttle body to the upper radiator. However after running the engine for a length of time long enough for the electric fan to come on (instr gage shows over 200), the thermostat doesn't seem to open up because the lower radiator hose is still cool as is the bottom of radiator, plus the radiator water level hasn't gone down since the initial fill. This indicates no flow into or out of radiator. Others have indicated we've probably still got a air bubble(s) trapped in the system but haven't described a precise manner to extract that devil of a bubble... Anybody out there provide a helping hand with a procedure ?
Staging Lane
Joined: Aug 2007
Posts: 73
Likes: 8
I read in a different forum to disconnect the upper hose from the radiator and fill the engine through the upper hose and reconnect. Then fill the radiator as you normally would. Seemed to work well. I do know from past experience that hot air will not effect the temp gauge or thermostat the way hot coolant will. As for the steam hose, I used a 4th gen f body radiator with the port on it right by the cap. While the engine is warming up I can watch until the steam port is a constant flow and that happened about the same time the rest of the system was purged of air.
