Help with Radiator

Hey Guys, I am trying to figure out what is wrong with my cooling system. I have done lots of searching and have lots of maybes.

What is happening is within five minutes of a cold start there is cooling spilling out of the radiator cap and bubbles in the reservoir.

This lead me to believe that it was a blown head gasket(one scenario)

But I replaced the radiator less than 1000 miles ago and because I am learning as I go I did not burp the radiator.

So I went ahead and took the cap off and started the engine and the only thing that happened was coolant was pouring out of the top. Now the radiator never turned on. NOW of course i didnt run it long because it was pouring coolant all over my drive way.

So, what do you all think? Its a 96 xj 4.0 HO aw4. Am I burping it wrong?

It doesn't need burping. Have you had your radiator cap checked or have you replaced it?

I did replace the rad cap

The 96 cooling system should burp itself with about 3-4 complete heat up / cool down cycles.

To rule it out, I would "temporarily" remove the thermostat. Just as a test though.

Has this engine ever been overheated? The best first test for a blown headgasket is to run a compression test on all cylinders. Low pressure on two adjacent cylinders indicates a blown gasket.

Another way that will definitively tell you is to use the rental "block tester" from Autozone, (think they are in VA) that you can rent.

http://www.autozone.com/autozone/accessories/Tools-Garage-and-Equipment/Block-Tester/_/N-25dh

If coolant is constantly overflowing from the open radiator throat (no cap), non stop, right after a cold start, it has a huge gasket leak.

If it slowly overflows, only after it gets warmed up, that is normal.