Hey Guys, 
   I am about to start a yblock that has had its cooling system and block drained, and now needs refilling with 50/50 antifreeze.  I have read that removing the thermostat, and filling through upper hose will help with not getting air bubbles in the system.  After good circulation, drain enough to install the thermostat, and refill.  Is this correct?  If so, do you just put a certain amount in that hose and fill the radiator, or can you fill entire system(roughly) through upper hose.  This is a stock 57 yblock system, running in just a stand     Can I just fill radiator with thermostat in and run engine, checking flow and bubbles?  Looking to avoid cavitation or hot spots from air bubbles.  If anyone has looked into this, findings would be appreciated.

Fill through the radiator cap.  Start the engine and let it warm up to operating temperature.  Mind the temp gauge.  If anything odd is happening, shut it down and investigate.  After a successful warm up, turn it off and let it cool completely.  Check coolant level and add if necessary.


Lawrenceville, GA

Am I wrong, or do modern thermostats have an air bleed hole?

6 VOLTS/POS. GRD. NW INDIANA

I’d close the cooling system up, like Charlie says, and if there isn’t an air bleed hole in the tstat, I’d drill one. I always do. Even if I’m breaking in a new cam, I don’t use antifreeze for break in runs. You're going to have to pretty much drain it to pull it off the stand and install it, I’d rather not deal with the mess of the antifreeze in the event of a leak or when I remove it. If you’re just running it in, you shouldn’t need freeze protection or the higher boiling point. Just water pump lube.

miker
55 bird, 32 cabrio F code
Kent, WA
Tucson, AZ

Remember to turn on the heater to get full circulation and no air in the heater



54 Victoria 312;  48 Ford Conv 302, 56 Bird 312
Forever Ford
Midland Park, NJ

Thanks everyone,
I had originally planned to do as charliemccraney says, but came upon this thermostat removal idea and wondered if it had any merit.  Hadnt thought about an air bleed in the thermostat.  If there's not, there will be.So much junk on the net, I had to check with those in the know.

Here's a method that has worked very well for me: Disconnect the upper heater hose attached to the intake manifold behind the thermostat  and elevate the hose a few inches. Then add coolant to the radiator until coolant just starts to run out the fitting on the intake manifold. Connect the hose and continue adding coolant until there is a level of coolant in there.  Warm up the engine, shut it down, allow it to cool down then top it off again if necessary. I have found this rapidly purges almost all the air from the engine assembly the first time. Hope this helps, JEFF...............


64F100 57FAIRLANE500

I do the same as FORD DEARBORN recommended..