HOW TO FILL A DRY COOLING SYSTEM WITH NO AIR LOCKS

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CFD244

CFD244

"I LOST MY ID IN A FLOOD"
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Hi Folks

Getting ready to break in a fresh 340. I have to fill the cooling system, and in the past I have experienced the odd air lock in other engines. What is the best procedure to fill it with 50/50 and be able to crank it to 2000 RPM for 20 minutes immediately after starting? Looking for a procedure that will guarantee a smooth break in with out an air lock causing any cooling problems. I have a high flow water pump and a high flow 180* Robert Shaw thermostat.

Please be specific........Rad cap on or off? Fill the rad, or leave it a little low? etc.

Thanks FABO
 
I have done this in the past...

Remove one heater hose from the manifold.

Put a funnel into the hose and with the rad cap off and the fitting the hose came off of open start adding coolant into the funnel.

The funnel should be the highest point in the cooling system.

Fill till coolant comes out of the hose fitting on the manifold

Cap that off and keep filling till the coolant comes out of the rad cap.

Re attach the heater hose.

start the engine.

Watch the coolant level in the radiator.

If the car is on a slight up hill tilt that helps too. Even front up on ramps is good
 
Dana67Dart said:
I have done this in the past...

Remove one heater hose from the manifold.

Put a funnel into the hose and with the rad cap off and the fitting the hose came off of open start adding coolant into the funnel.

The funnel should be the highest point in the cooling system.

Fill till coolant comes out of the hose fitting on the manifold

Cap that off and keep filling till the coolant comes out of the rad cap.

Re attach the heater hose.

start the engine.

Watch the coolant level in the radiator.

If the car is on a slight up hill tilt that helps too. Even front up on ramps is good
Click to expand...
I should be more specific.........

The engine is on a run stand with no heater hoses. WP and intake heater ports are plugged. Thermostat and housing are not sealed yet. Rad frame and rad will be installed after oil priming and manual rotation.

20231203_181412[1].jpg
 
We ran a T in the rad hose to pump in cold water with from a hose with a valve and a T that let water out of the system to keep the temp within range.
 
If you use flex rad hoses you can keep the filler of the rad as the highest point. Use the water hose and push a few extra gallons of water through the system to push out the air. On our dyno the top of the water tank is about a foot higher than the top of the motor and we pump water through before even starting the motor.
 
Post #2 and #9 will get you there, very easy and 100% effective.
 
toolmanmike said:
That's what I used on my 66. I didn't add any coolant after break in.
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I didn't realize the engine was on a run stand. Mileage may differ. I've filled huge cooling systems with that tool. It has a bit of a learning curve
 
You are worrying about nothing. Do you think the factory went to all the trouble described in some of the above posts?
Capacity [ full ] is about 16 qts [ or more ]. There might be 1/2 a qt or a little more of air. A very small percentage. The coolant is in constant motion removing heat & air pockets.

That TQ looks like King Kong, probably sound like him too....
 
Bewy said:
You are worrying about nothing. Do you think the factory went to all the trouble described in some of the above posts?
Capacity [ full ] is about 16 qts [ or more ]. There might be 1/2 a qt or a little more of air. A very small percentage. The coolant is in constant motion removing heat & air pockets.

That TQ looks like King Kong, probably sound like him too....
Click to expand...
Just slowly fill the system give the air time to leave the system. A little different with modern plumbing
 
Drill an 1/8" hole in the thermostat, this lets the trapped air out of the block and heads.

Screenshot_20231204-005730_Gallery.jpg


Make sure that you get a full 4 gallons of coolant into the engine, then you know it's full.

☆☆☆☆☆
 
George Jets said:
Drill an 1/8" hole in the thermostat, this lets the trapped air out of the block and heads.

View attachment 1716173995

Make sure that you get a full 4 gallons of coolant into the engine, then you know it's full.

☆☆☆☆☆
Click to expand...
This right here ^^^^^^, but really what Bewy said. The factory never worried about it. If you're gonna lose sleep over it, run a thermostat with a bleed. All HP high flow thermostats have them anyway, which is what you should already be running.
 
I air locked a 440 once. ALL you need do (and the stat vent hole is a good idea) is to disconnect the heater BELOW the T stat on the intake. You say you don't have a heater, but you DO have a pipe plug there. Just remove the plug. Another way would be to pull off the top end of the bypass hose.

If you don't have sealant on the t stat housing, you could also remove the water neck and t stat, "gently" crimp the top hose and tie some twine around it while doubled over, etc, and then fill until you get coolant up in the t stat area of the manifold.

Still another way is to temp install a petcock/ valve in the lower heater hose fitting at the manifold to bleed it.
 
Probably not a problem with that thermostat. Not really an issue with "regular" flow systems, only the newer systems with reverse flow have trouble. If you really want to be sure, replace a manifold heater fitting with a 6" piece of pipe and a bell reducer at the top, you'll need a threaded cap for the bell reducer. Or do like post #9.
 
Bewy said:
You are worrying about nothing. Do you think the factory went to all the trouble described in some of the above posts?
Capacity [ full ] is about 16 qts [ or more ]. There might be 1/2 a qt or a little more of air. A very small percentage. The coolant is in constant motion removing heat & air pockets.

That TQ looks like King Kong, probably sound like him too....
Click to expand...
The 318 I put on the stand, filled it with coolant......When it got to 220* I shut it down and it blew coolant all over the garage like a volcano (ran with a loose rad cap). I let it cool, topped it off and everything was fine after that. I don't want this happening with this 340.
 
Thanks for the advice everyone. I'll fill the engine up from the intake first, then top off the rad.

I'll have to take a closer look at my Robert Shaw to see if there are air bleeds in it.

:thumbsup:
 
The RS type stats have a notch in the rim to let air escape. A lot of holes are put in stats that don't need to be added.....
 
CFD244 said:
The 318 I put on the stand, filled it with coolant......When it got to 220* I shut it down and it blew coolant all over the garage like a volcano (ran with a loose rad cap). I let it cool, topped it off and everything was fine after that. I don't want this happening with this 340.
Click to expand...

Did you fill the block with coolant through the thermostat housing before installing the t-stat? I had a similar incident the first time I overhauled the original 318 in my Duster, since then I've just filled the block before putting in the t-stat and it's been fine.
 
CFD244 said:
The 318 I put on the stand, filled it with coolant......When it got to 220* I shut it down and it blew coolant all over the garage like a volcano (ran with a loose rad cap). I let it cool, topped it off and everything was fine after that. I don't want this happening with this 340.
Click to expand...
It will if you leave the cap loose. Every pound of cooling pressure raises the boiling point 3°.
15# cap = 45°. Shut off a hot engine with no pressure and it superheats the coolant. It doesn't take long for it to get over 212°.
 
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