Overheating

First you need to verify you did not get an air pocket in the cooling system. Here is the procedure for bleeding. First pic is the air bleeder. Second pic is the heater bleed. Here are the instructions

Filling-Bleeding
On 3.9L engines

Remove the engine fill cap.
On 3.0L engines

Open the engine air bleed.
On all engines

Open the heater air bleed.
Add coolant to the degas bottle allowing the system to equalize until no more coolant can be added.
On 3.0L engines

Close the engine air bleed when coolant begins to escape.
On all engines
Replace the degas bottle cap.
CAUTION: Care must be taken to ensure the accessory drive belt does not become contaminated with engine coolant.

On 3.9L engines
Add as much coolant as possible to the engine fill. The heater air bleed will remain open.

Replace the engine fill cap.
On all engines

Note: The heater air bleed remains open.
Start the engine and turn the heater to MAX position.

Close the heater air bleed when a steady stream of coolant comes from it, during engine idle.
Allow the engine to idle for five minutes, add coolant to the degas bottle as needed to maintain the cold fill MAX mark.

Reopen the heater air bleed to release any entrapped air and close again.
On 3.9L engines
Maintain engine speed of 2,000 rpm for 3-5 minutes or until hot air comes from the heater.
Return to idle and verify hot air is still coming from the heater.
On 3.0L engines
Maintain engine speed of 1,500 rpm for 3-5 minutes or until hot air comes from the heater.
Return to idle and verify hot air is still coming from the heater.
On all engines
Set the heater temperature setting to 24°C (75°F) and allow the vehicle to idle for two minutes.
Shut the engine off and allow to cool.
After the engine has cooled, add coolant to the degas bottle to bring the level to the cold fill MAX mark.

According to the diagram, it looks like it is on the driver side firewall. Looks like next to bottle. Here is another picture with the cowl off.

The second picture. If you cannot find it try to bleed from the bleeder in the first piture. Turn heater on. When a steady flow of coolant comes out, shut vehicle off and let it cool down and repeat the step if you see the level drop in the bottle.

Only to fill with coolant.

Yes only add yellow. Please let us know if this fixes it.

Cheers, Ken

They can mix and cause coagulation but in most cases you will be okay.

Unfortunately the head gasket chemical test is only about 75% accurate you can still have a blown head gasket. Lets try this remove all of the spark plugs to check if one or two of them look different than the rest. This will be the induction of a change in the combustion chamber.

Because the heater core fills with air and you constantly need to add coolant is a sign of a blown head gasket.

Did you ever find the heater bleeder? Also you may want to try a new expansion tank cap if you have not replaced that yet? And as Ken suggeted, remove the spark plugs and see if anyone of those look different? You may need to do a cylinder leak down test.