Radiator foaming out of cap

I did a search here and on google and am hoping for the best. I'm new to jeeps. I've owned this for 5 months. 2000, 4x4, 4.0, automatic, 189k miles.

Since owning it I've put on 10k miles and it has run like a champ and still is.

Here is the problem. Yesterday I noticed antifreeze under the jeep after driving 15 miles. I checked the level right then and it looked normal. Today I made a short 2 mile drive and when I got to my destination I saw it dripping. When I opened the hood there was bubbly, almost like foam, antifreeze coming out from the radiator cap. After letting it cool a bit I removed the cap and the fluid level was low, it took two 16 oz water bottles to top off.

Once home I did some reading and see that it could be the head gasket or cracked head or for all I know this is normal and the cap is bad.

I've changed the oil three times since owning and each time the oil looked normal. Oil on the dip stick today looks normal. Jeep seems to be running normal and temperatures seem just fine, 200+/- on the gauge. I have not tried an alternate heat reading yet to verify the gauge in the dash however I tend to believe the gauge and sending unit is functioning properly based on watching the temperature changes during various driving conditions. In the morning the tail pipe drips water but goes away once warmed up.

No white smoke or check engine lights and passed smog with flying colors when I purchased it. So, before I go crazy on the engine I took this short video of the bubbling and was hoping for some pointers on things to check before declaring head issues.

I am certainly going to drain and flush as there is brown sludge in the neck beneath the cap, not sure if that is an indication of anything either. The radiator was replaced by the former owner just prior to me buying. Looking at the radiator it looks like it was installed last week.

One last thing, may or may not matter. On Saturday I was offroading, it had just rained so there were lots of puddles and a couple water crossings. I find it hard to believe splashing water on a normal engine could cause a cracked head. I only mention it because this started happening the day after.

Here is the video and I appreciate any input on various things to check into as possible causes.

http://www.youtube.com/watch?v=DTpe6bP_7Ro&feature=share&list=UUrxX8prSbA6Ae1OdCL2oMFA

I would change the radiator cap before jumping to any conclusions. Even if the cooling system is pressurized by exhaust gas it should open the pressure valve on the rad cap and send it to the coolant reservoir, not leak out the top of the cap. Also, may sure the line to the reservoir is clear.

The typical crack location for your 2000 head is under the valve cover between #3 &4. You can remove the oil cap and look down at that exact spot. This common location won't push combustion pressure in to the cooling system but coolant into the oil.

Any how, change the cap, make sure the radiator neck is in good condition, check the hose to the reservoir, top up the coolant and see how it does.

Thank you for the reply.

Tomorrow I'm going to flush the entire system, ensure the overflow hose is clear and replace the cap. Hopefully that is the last of it. I'll also peer down into the head.

Much thanks!