Where to start, I had a friend in a '00 TJ running about 45 mph down the road and anti freeve started gushing into the floor boards and steaming under the hood, temp guage read 210 but instantly pegged once the water started flowing. Drug t home, found that there is a massive leak in the radiator just under the plastic top. It has a bad bad miss now, the plugs are probably as bad as I've ever seen any, black and gapped bad. I think the plugs are the answer to the miss, friend said he doesn't think they have ever been changed. Understand the water under the hood because the radiator leak, but I'm lost on the water in the floor board. My first thought is the heater core but what's the odds of it going bad at the same time the radiator blows. Sorry for the long story but wanted you to have all the details. Any ideas on where to start with the water inside would greatly be appreciated. OH, already replaced the plugs and have a ratiator on order.

Sorry to hear of your friend's misfortune. Hopefully there's no significant permanent engine damage.

Can't help but wonder if the interior leak & the popped radiator have the same root cause -- a massive pressure buildup in the system. That would also explain the overheat, too (if the water stopped circulating before it blew).

After installing the new radiator, you may want to test the system integrity with water *before* adding coolant -- it will be a lot easier to clean out of the interior if the heater core is blown.

Good luck!

BlackJack

My heater core was clogged this past winter. it didnt leak or anything but i had no heat. Coultdnt figure it out till i took the hoses off of the heater core from under the hood and ran water through it.... well id didnt really run. Finally cleaner it out and had heat. i know that's kinda off topic but just goes to show that it could be clogged pretty bad in there i was just luckey that it didnt blow anything. like BLKJK said test with water, but since the coolant will be out try flushing out the heater core and see if it is clogged or broken too. Maybe one of the hoses just popped off and shot coolant beside the copper pipe onto the floor. good luck

Thanks guys!!! I found on stu-offroad directions to replace the heater core. looks like a pritty big job but I think I can find a bigger hammer if need. haha

We have a new radiator on order, should be here tomorrow. Picked up hoses, cap, trans cooler, spark plugs, and thermistat at the local parts store.

My friend forgot the heater core so he's going to try to get it today. I've noticed there's not any after market like from 4wd or one of those places. I hope its not a dealer item that takes six months to get here.

Planning on working on it this weekend. I'll let you know what we find.

Best of luck with the job! With just a little of that, this could even be a fun weekend project.

Yes, please do let us know what you find.

The heater core is a bigger job than the radiator - the rad can take two to four hours depending on your experience - but the core took me almost a day - with all the tools and the hoses.

If you can use a pressurization tool to pump the pressure up before you heat the engine up you can check for leaks before you start putting expensive fluid and coolers in. I have a Stant with an adapter for Chrysler radiator caps.

If you overheated the head you might have cracked a plug so that might be why it is missing - but depending on how lucky you are
there could be issues with a cracked head...

Clean an flush the system and then clean the engine and look for oil and water leaks on the head. You are looking for oil scum and froth in the radiator and leaks down the side of the engine block were the head meats the block.

If you have the radiator out - get a new FlowKooler water pump and put it in while you
have the room.

Stress continues!
We couldn't wait until this weekend so he took off work today and I left a little early.
We pulled compression on the cylinders number six was 170 lbs and the rest were around 40 lbs except for number 2 it was zero. We pulled the thermostat and it was stuck open and the tip was bent. Pullled the head the gasket appeared to be burnt between 2 and 3 cylinders and 5 and 6 cylinders, making me think gasket failure. But wait it gets worse. On the cylinder walls was what we first thought was grooves just on the fire wall side of the cylinders. But after picking at them for a bit we think it is something like carbon build up. And on the top edge of the number 2 piston were three fresh dings on the radiator side that almost looked like you hit it with a hammer. There was not a mark on the head to match it so I can't explain those. We THINK the thermostat locked closed, which allowed the moter to get really hot and still show normal temp. cause the temp. relay is on the radiator side of the thermostat. Show you've got HOT water in the motor, cold water in the radiator and when it finally built up anough pressure to bend the thermostat and pop it open and the hot meet the cold. It pop the radiator and the heater core. OH He said he had been smelling anti-freeze for a while so I think the heater core was ready to go anyway.
As for the head gasket and cylinder walls. I think when the motor got that hot, the metal expands and contracts with heat, causing the carbon to come loose and it didn't have any where to go but in the cylinders, causing the build up on the walls, which was bad anough to make the rings not seat properly, and cause the miss.
These are just my ideas. I'm not nor have I ever clamed to be a mechanic. I can take anything apart and put it back together. Usely I can figure most things out but honestly I've never done much motor work. Just the basic.
He has another friend who is a mechanic and has been for years coming over to give a second opinion tomorrow. He is retired and refuses to work on other peoples vehicles any more but we called him and he agreed to come take a look cause we had already done the work and we were just needing an opinion.
Priced a new long block just in case a $1,800.00 with a 3 year free replacement warranty. Machine work for the block and head priced at just over $900.00.
Hopefully we'll know more tomorrow.

There is a bypass whole so there will be some level of water flow
even if the thermostat is closed - it can get clogged.

But the cylinder pressures say it all - total melt down - one of the
reasons I use a Raytheon infrared temp handheld is so I can do a
temp run across the entire engine - and know where when and where
an engine is overheating - and when I even suspect there is an
issue - I have it out and I am checking.

Out here in AZ I have to have my rig at 120% or I will die in some
canyon ten miles from home...