Hey guys. I promised to give an update as it rewards the good ideas of people who helped me figure out my JK.
I used the funnel kit from Amazon.
https://www.amazon.com/gp/product/B01I40ZQWE/?tag=jkforum-20
I put the front end about 12 inches high with a floor jack. I ran it and watched it. Did nothing for the first ten minutes or so. I went inside for a snack. Came out and the fluid in the funnel was boiling. Jumping. Was all over the front of the car. It was crazy. I added fluid and it calmed down. Maybe made the thermostat close? Then I turned the car off. Immediately the fluid drained into the radiator. All of it. Fast. So I went and grabbed another gallon and started pouring. Poured in a whole gallon.
Then I waited about an hour and tried it again. Same thing. Not much until the thermostat opened then the fluid went crazy. Lots of air. Lots. So I was ready. Poured fluid into the funnel. Everything calmed down and the fluid had a very occasional bubble. Then when the thermostat opened it went like lava from a volcano. So I turned the car off. Poured extra fluid in the funnel and sucked in about half of the extra.
So then I had a funnel with hot fluid and had to take it off. Went everywhere. My wife helped me try and get it into a container. Total disaster. Hilarious.
Then I took the car for a drive. The gurgling in the dash was gone. The thermostat never went over straight up. Heat was working again.
And the strangest thing, the fifth cylinder stopped backfiring. I wasn't able to get emissions on the car and renew the tag since the engine light was on with the back fire. Now it runs great. My son returned our family suburban and he took the Jeep back to college.
So, what in the hell is going on?
My best guess: there is a head leak from cylinder 5 into the radiator fluid and somehow these things are all related. I am not a mechanic. Not even a weekend warrior mechanic. I was an Army Chaplain for the 187ORD Battalion at Fort Jackson where real mechanics learned their trade. I never picked up a wrench to fake that we had something in common. Would love to know your opinion.
Anyone have an idea?