I decided it was time to swap out the antifreeze in the jeep. I drained from the petcock on the radiator then pulled the lower hose from the water pump and let it drain from there. I filled it up with just water and let it run a couple minutes then drained from both places again. I then added water/antifreeze and left the radiator cap off and started it up with the heat on high like my haynes manual said. Coolant started bubbling out of the radiator and the temp climbed real quick and didn't stop till i cut the jeep off. I checked and the radiator and all the hoses were still pretty cool, definitely not 240*. I let it cool for a few minutes then tried it again, it did the same thing. My first thought is the thermostat but it was working fine before the flush and is only ~6 months old. Any ideas why it is heating up so quick and why the coolant is pouring out of the radiator?

 

your water pump is cavatateing........what i normally do is squeeze the lower radiator hose and fill at the same time....this helps to "prime" the sytem and get the air bubbles out....TRY IT.

 

I guess this could cause it to overheat because the waterpump ain't pumping?

 

I put my XJ up at an angle on ramps and it fills fine.

 

You might try removing the heater hose from the thermostat housing. I would think that would allow trapped air to escape and fill the block as you fill the rad.
Otherwise if you remove the same hose (carefully) from the diverter valve (if installed) you can pour antifreeze right into the engine.
Rich

 

plus one on the water pump cavetating. That just means theres air in there, and it ain't doing it's job. Squeezing the lower hose as was suggesting (With the motor off and cool please, that electric fan would mess you up bad) should fix that puppy.

 

I tried squeezing the lower hose and got some air out now the upper hose gets hot once it's up to temp like it should but the temp keeps on climbing. Also, the heat doesn't work, it blows but it's not hot.

 

There's air in your heater core sounds like. These systems are a b*#^$ and a half to bleed...

 

You've still got air in the system. Keep on slowly squeezing the lower hose.. sometimes it takes a while to purge all of the air.

 

Any tips on how to get it out of there?

 

What he said.

Also, some one else said put the front end up on ramps, that helps too. I just parked mine up on a curb and that did it, haha.... ghetto ramps...

 

I finally got it! I went back out after letting the jeep cool for a while and the overflow bottle was empty. I filled it back up and then squeezed the lower hose while adding more through the radiator cap. I filled it up until it wouldn't take anymore then let go of the hose. It let out a big gurgling "burp" and I knew I had it. Started it up and let it warm up, turned the heat on and there was heat. The gauge got to about 215-220 then went back down to ~190 just like it always has.

One last question though. Has anyone ever used any of the coolant additive? I saw it at work the other day and wondered if it was any good. It claims to help with cooling and and fight corrosion. Anyone use it with good results?

 

What additive?