Air getting into cooling system

This is normally caused by a restriction somewhere in the system. If it wasn't doing this before you replaced the thermostat, just make sure you installed it correctly. I can't remember but I am pretty sure this only goes in one way to prevent you from putting it in upside down.

Then we need to use a laser temp gauge to check around the engine and cooling system to see if we have any hot spots as that would be a restriction. Check the radiator as well. Clearly you should have a decrease in temp but it should be gradual as you go down the radiator.

I just had a newer Jeep that was doing the same thing as this and we found the small return line to the overflow tank was restricted and it caused the tank to overflow and just a constant stream or air to come out of the bleed valve by the radiator.

Let us know what you find and we can go from there but I am pretty confident you have a restriction, we just have to find it.

It sounds like you bled the system as it was possibly needed and maybe beyond.

Sometimes oil getting into coolant or coolant getting into the oil is a usually a sure sign that a head gasket failure may be the problem.

Sometimes overlooked is a head gasket failure in which combustion gasses (air/fuel and, or exhaust) pushes through the damaged gasket into the "compartment" shared by that portion of the head gasket. That might be oil or coolant, sometimes it spits out of the exterior of the engine into open air.

Here's a 2CarPros YouTube guide on how you can test for head gasket problems:

https://www.youtube.com/watch?v=5zpNjYmmiYY

Let us know what your findings are.

The Medic

Let's check for a restriction in the system by checking the temperature around the engine and cooling system to see if there is a hot spot.

Okay. Sorry for the delay. Those do not seem to be too bad so I would not think you have a blockage. However, I just thought that because this is a 2.7L it does have a bit of an odd process. I attached what needs to happen to ensure you don't have air pockets. Take a look at this and let me know what you find.

The behind the housing would be correct. As for the leak, I doubt that will cause it but it clearly should be corrected.

If you have filled it to the top,

When it heats up, you (and all of us) will experience "Thermal Expansion".

In simple terms, your 2 gallons of water has turned into 2-1/8 (or so) gallons of water.

2-1/8 gallons will not fit into the 2 gallon space.

It will push out all that will not fit (down to the 2 gallons of hot expanded water that will fit)

You get home and go to sleep.

The water cools, in the morning you snatch off the cap, you are an inch or so low. Wild guess, you now have 1-7/8 gallons in there.

Take it down the road, the water is hot (and expanded). The "inch low" is now to the top, the water has expanded back to 2 gallons, the radiator is full.

As long as everything remains great and fine the water will not push out anymore unless you add some. Or you have some overheating.

Moral of the story, a little low is normal (you will learn as time goes on, looking into a cool radiator).

You still must "maintain" that level (cold)

I have made Popsicle sticks/ similar device with a mark on it to verify what my "normal" cold level should be, I would store them in a crevice in the hood's underside.

As with the oil, your owners manual says to check it "weekly". Performing all of your Jeeps scheduled maintenance will make him last forever!

You can mix your coolant 50/ 50 to 70/ 30

I always do 70/30 so that if I'm forced to add plain water in later, I'll still be with the tolerance!

Always mix the coolant correctly in vessels prior to pouring it in your Jeep. There is no "wrong" guessing doing it that way. No matter if you need 1 gallon or 10 gallons, now or later, the mix will always be right even with some still in the system.

The Medic

That's some good news!

We appreciate you taking the time to give the thread some closure, other folks may benefit when they read your thread.

Be sure to come back!

The Medic

Just catching up on this one. Glad you found it. Restrictions in these systems cause all sorts of odd issues. As was mentioned, thanks for updating us. That info will surely help others. Talk to you next time. Thanks