Vintage Mustang Forums banner

1 - 10 of 10 Posts

·
Registered
Joined
·
31 Posts
Discussion Starter #1
Rebuilt 351c, getting close to the initial fire up. I've seen some how to's on purging air from the system with the engine on, but nothing on how to do it with the engine off. Any tips or tricks?
 

·
Registered
Joined
·
6,143 Posts
it's done when running- otherwise the thermostat won't open to allow the air to pass through and out.
 

·
Registered
Joined
·
263 Posts
Top tip, drill a 1/8" hole in thermostat perimeter to aid in circulating trapped air.. hopefully yours is not fitted yet, but, a quick and worthwhile job nonetheless..

Sent from my SM-G950F using Tapatalk
 

·
Registered
Joined
·
262 Posts
What I do when filling up the engine with coolant/water is:
Assuming engine cold:
(1) Turn the heater to "on" so that coolant will fill/circulate through the heater core
(2) Take out the temp sending unit from the manifold. Fill up with coolant until it's about to come out of the temp sending unit hole. Replace the temp sending unit.
(3) Fill with coolant the rest of the way until it just covers the radiator fins
(4) Start the engine and let it start to warm to operating temp
(5) Add coolant as needed. When the thermostat opens the level usually drops (having a IR temp gun to check the temp of the radiator hose is useful in gauging just when this is occurring)
(6) When you don't see any more bubbles in coolant in the radiator, you're done. Radiator cap on. Engine off.
(7) Later, after the car has cooled down, check the level. Coolant should just cover the radiator fins. Not any higher.

+1 on putting a small "breather" hole in the thermostat. Helps "burp" the system. Some thermostats already have them.
 

·
Premium Member
Joined
·
4,359 Posts
Radiator cap should be at the highest point, car pointed slightly uphill to help get air out of the heater core helps.
 
  • Like
Reactions: 65coupei6_2

·
Registered
Joined
·
133 Posts
What I've always done is to remove the heater hose (where it plugs into intake manifold) and fill SLOWELY until I get water up to the fitting. Then when it's there plug the hose back in. If you do not have a spring in the lower radiator hose you can hand pump that to try to get the air "up". Just what I do. Mel
 

·
Registered
Joined
·
154 Posts
On a 351c also make sure you are using the proper thermostat, with the hat on the end to close off the bypass, otherwise the engine will overheat.
 

·
Registered
Joined
·
5,237 Posts
we are the original family owners of my 351C

In all these years and all the coolant changes I never had any issues with this motor trapping air

if you want to take the extra step, as mentioned b4 removing the stat or sender b4 filling is a good idea
but imo not necessary
 
  • Like
Reactions: cougar70

·
Registered
Joined
·
35,930 Posts
Park car on a relatively steep hill or on ramps with the nose facing up-hill.

Remove the radiator cap.

Start and run the engine until the thermostat opens and coolant begins to circulate.

Add coolant as needed and wait for thermostat to open again.

When finished, replace radiator cap and turn off engine.

When cold, check coolant level.
 
1 - 10 of 10 Posts
Top