How to use the Coolant plug / bleeder?

[J33Pfan]

I went through the "HOW TO: Flush/Change Coolant" and didnt see much info on the coolant plug above/atop the engine.
I've used it to bleed air and fill Antifreeze but not actually sure of its proper purpose.
Does anybody know what the actual use for this is?

 

[uss2defiant]

#1 on the diagram?
That's the air bleeder.

 

[dude1116]

I went through the "HOW TO: Flush/Change Coolant" and didnt see much info on the coolant plug above/atop the T-stat housing.
I've used it to bleed air and fill Antifreeze but not actually sure of its proper purpose.
Does anybody know what the actual use for this is?

You're supposed to back it out a little bit while the Jeep is running. It'll then produce a small amount of coolant and some bubbles. When the bubbles stop happening, you've purged most of the air out of the system.

Also as an FYI...the T-stat is at the lower hose...not the upper like the bleeder is.

 

[HoosierJeeper]

You open it, coolant sprays out on everything, you close it, and cuss for the next hour while you clean it up.

 

[GunnerSchenck]

If I was you, I'd double check you use the correct hex head on it as well.. if you use one that's "close but works" it may force your twisting tension to one side of the screw or the other.. once they're stuck, they're frustrating. But can be replaced cheaply with plug screws sold at autozone. Just a heads up

 

[GunnerSchenck]

You open it, coolant sprays out on everything, you close it, and cuss for the next hour while you clean it up.

I just wrap a cloth around it while I loosen it..

 

[HoosierJeeper]

Too easy/logical.

 

[tjkj2002]

If replacing anything in the cooling system remove plug and place a small diameter funnel in hole and fill from there 1st.Once full then add coolant to the tank so that way the block get's filled 1st.