Problem started a couple of weeks ago, overheating, would go from 210 to 260 in a snap of a finger. Nasty brownish/gold sludge in the recovery tank, figured same stuff was on the thermostat, changed that. Flushed the radiator best I could, put everything back together ran fine for a week, then same thing happened. More nasty crap in the tank, after a little research I found this forum after searching around, found it could be the headgasket. Just compression tested starting from front to back in PSI- 1-152 ,2-152, 3-152, 4-120, 5-70, 6-152. I rechecked #4&5 twice came up with the same number. Sound right being a headgasket issue? I can't afford someone else to do it, but I have plenty of time a garage and plenty of tools. Any input appreciated. BTW it's 99' cherokee 4.0. On another note my repair manual says that to remove the trans. cooler lines from the radiator it requires a special tool. Ever heard or ran into this? THanks.
Charlie

 

Could be head gasket, valves, cracked head.

Pull the head.

No need to pull the tranny lines just to remove the cylinder head. No special tools needed anyway.

 

im in the middle of doing my head gasket, its fairly easy, just be patiant and CLEAN CLEAN CLEAN everything with alot of care, theres alot of little crap to clean out, but go for it, i wish i had a garage , ive been doing mine in the snow

 

Remove the radiator cap and watch the coolant while you have someone start the Jeep. Usually a bad head or head gasket will make the coolant jump up when started.
Just an old trick I learned years ago... One more piece of the puzzel so you don't feel so bad about removing the head.
You can buy those tranny-line disconnect tools at your local auto parts store. There not too much and you can undo fuel lines and AC lines as well.
Mike

 

Before you put it all together take a tap and chase the threads in the block to prevent incorrect torque values and premature headgasket failure

 

You could try and dump a little oil in the 2 suspect cylinders and compression check it again. Blow a little air in there with an airhose so it coats the complete bores. Allow it to soak for an hour or so and check it again. If it checks better after that you may have bad piston rings.
I don't recall the exact amount of oil to add or how long to let it soak but I'm sure if you Google it you'll find the info.
Mike

 

Thanks, all good info. The coolant does jump up when started, I'm pretty much convinced there's something going on there, whether headgasket or cracked head. While I have everything apart I wanted remove the radiator and flush it real good and try to get the draincock unplugged. Theres so much crap in the cooling system, I want to start fresh and have no restrictions anywhere. I'm sure I'll be back with more questions later. Thank for the help, great source for info. and support.
Charlie

 

Dont Skimp take it to the machine shop and have it Magna fluxed. My head on mine 98 was cracked in 2 Spots and had no coolant burning issues.