Bleeding air from cooling system

['94IDITurbo7.3]

I am in the process of finally filling up my cooling system.

Do i just fill the rad up with the required amt of fluid, then start the engine and let it run to get the air out, then top the rad off once all the air is out, then fill the overflow tank to the right level?


How long should i run the engine for? Do i run it with the rad cap off to let the air out?


Thanks

 

[icanfixall]

There are several ways to get the trapped airout of the cooling system. Some will remove the hose from the head to the heater core. That vents the air. Some will use the special vacuum tool that pulls a vacuum on the cooling system. Then sucks in the coolant... Thats the best system but the tool is expensive. Hopefully your check valve in the thermostat head is operating. If it isn't you may need some work to get all the air out. What has always worked easy for me is fill the system. Then fill the overflow tank to proper level and start engine with cap on tight. Bring up to temp by a short drive around the block. Do not drive too far. You may have lots of trapped air inthe heads and thats a bad thing. Let the engine cool down. Any trapped air hopefully is pushed out into the overflow tank. As the coolant cools down it creates a vacuum in the cooling system. Then the coolant is sucked back from the overflow tank refilling the void in the radiator. Check the overflow tank for proper level every morning after a refill. This refilling may take a few days but it works every time. Just make sure the tank has enough coolant to refill the radiator and the suction line is open and clear of plugs.

 

['94IDITurbo7.3]

Thanks Gary

I will try that.

 

[Late_99_psd]

The bast way is to just "Burp" the system by lightly squeezing the upper radiator hose after you get the radiator filled. You'll see the bubbles come out. Keep burping it untill the bubbles stop, or slow down anyway, and you system will be purged.
After you get it started turn the heater on full blast. If you have heat, then you got all the air out (since the heater core is the higest part of the system.)

Always done this method and it has never failed.

 

[icanfixall]

Coolant flows thru the heater core no matter if you are using it our not. All that happens when you push the dash heater thingy is it opens the vent door in the air ducts...Some members here have installed shutoff valves to stop the flow of coolant thru the heater core.When that done your ac gets much colder because no hot coolant is being pushed thru the core.... Some are manual valves and others are vacuum operated valves.

 

[Black dawg]

on my truck I have one of the coolant flush fittings in a heater hose up high by the alternator. I just take the cap off of it and slowly fill up the radiator. after you get the radiator full, just leave the lever on your lever vent cap up, and the remaining air will work itself out.

 

[Late_99_psd]

Coolant flows thru the heater core no matter if you are using it our not. All that happens when you push the dash heater thingy is it opens the vent door in the air ducts...Some members here have installed shutoff valves to stop the flow of coolant thru the heater core.When that done your ac gets much colder because no hot coolant is being pushed thru the core.... Some are manual valves and others are vacuum operated valves.

Yes, but you don't know if its flowing through unless the heat is on.

 

[icanfixall]

Coolant always flows thru the heater core. This is a science fact. Look at the inlet hose and the outlet hose... Any valves on them... Nope... So its always flowing hot coolant..... It does not matter if youare using the heater or not. That lever just opens a door in the ductwork...

 

[vegas39]

Coolant always flows thru the heater core. This is a science fact. Look at the inlet hose and the outlet hose... Any valves on them... Nope... So its always flowing hot coolant..... It does not matter if youare using the heater or not. That lever just opens a door in the ductwork...

Thats right, always hot. I put some shutoff valves on mine with a bypass.

 

[7river]

Coolant always flows thru the heater core. This is a science fact. Look at the inlet hose and the outlet hose... Any valves on them... Nope... So its always flowing hot coolant..... It does not matter if youare using the heater or not. That lever just opens a door in the ductwork...

If it is airbound, you may only have coolant flowing in the bottom 1/4 of the hose (or maybe none?). You wouldn't know this unless the fan was on to feel the heat. I think that's what Late_99 was saying. I've had that problem on large diesel plants and domestic heating systems.

 

[7river]

When I was refilling my bus I filled the rad to about 6", left the cap off and the started. Hoses all got hot, thought I was good but I guess when the thermostat opened it started overflowing. I think it was air trapped in there. I guess it could be thermal expansion but seemed like a lot.
Boy, I hate spilling antifreeze.

 

[Late_99_psd]

Coolant always flows thru the heater core. This is a science fact. Look at the inlet hose and the outlet hose... Any valves on them... Nope... So its always flowing hot coolant..... It does not matter if youare using the heater or not. That lever just opens a door in the ductwork...

Yes I realize this. All I'm saying is if you have heat, you have coolant flowing through the heater core. I the system is air bound the coolant will NOT flow through because the air will float up to the higest point in the system. Yes, a little coolant may flow into it, but you wont feel any heat out of the ducts.

If it is airbound, you may only have coolant flowing in the bottom 1/4 of the hose (or maybe none?). You wouldn't know this unless the fan was on to feel the heat. I think that's what Late_99 was saying. I've had that problem on large diesel plants and domestic heating systems.

Yes, thanks

 

[6 Nebraska IDIs]

Ok, I've tried everything in the book and some things not in the book and honestly, this little tool here is priceless.
http://www.tooldiscounter.com/ItemDisplay.cfm?lookup=LIS24610&source=froogle&kw=LIS24610

Don't go directly to a store to get it, print out that website and take it to an advance or oreily autoparts and have them price match it and order it in for you. Normally that thing is like $45. I just found you the deal of a lifetime there.

I park my vehicles at an incline and put the funnel on, fill the system until the funnel is about halfway full and run the engine for about an hour. Some systems burp in less than 20 minutes. But out trucks seem to take forever. This is the only sure way I've ever bled out all the air in a cooling system.