New Guy, Bad Head Gasket?

About a year ago, I bought a 01 Cherokee(4.0, auto) so I could keep wrenching on my 80 cherokee and have a reliable DD. HAd about 60K when purchased and drove flawelessy for the 15k I had put on it so far. Yesterday, I drove 80 miles to the airport going about 80 mph, kept an eye on the gauges(forceful habit from my fsj!) gauges were fine the whole way down, no problems. Pick up girlfriend, hop in the jeep, take off, no problems. Was a little chilly, turn on defrost notice there's no heat coming out, check gauges, still normal. After a few miles, I hear a slight ping on acceleration, sounded almost like spark knock, start getting concerned. Knock gradually gets louder, in a construction zone w/no shoulder, start praying for an exit. About this time, temp gauge shoots all the way in the red, then move back down slightly higher than it should, pinging gets louder, finally hit an exit, dies halfway up the exit ramp. Total distance from the first ping to exit was about 10 miles, temp surge was about the halfway point. Pop the hood, coolants completely gone, engine is hot, it's about 10pm, raining, no flashlight, tools, nada. Run over to gas station, buy water ,flashlight, run back, try starting, cranks, acts like it wants to go but no luck. 3 hrs, 60 miles and 250 bucks later, I finally get home thanks to Joe's Towing Co. Dig into it a little, block around the head gasket seems a little "moist", engine was pretty clean, only have about 75k on it, so I start suspecting the head gasket. Check are around the radiator, some spillage around the cap but I've seen alot worse. Check overflow resevoir, has a little fluid but not very much at all. Fill it up radiator, no leaks. Check the oil, right level, does not look milky, drain it and find nothing but oil, start doubting my previous diagnosis a bit. Run a compression test:
#1-60
#2-0 -(poured a little oil in cylinder, retested, no change)
#3-60
#4-90
#5-120
#6-120
Had the valve cover off during the comp test, everything was moving as it should with the exception of the pushrods on #2: they went up and down but did not spin around like the others do(never seen them spin like that before). You guys think it's my head gasket and/or something much more sinster? If so, where the heck did all my antifreeze/water go? I checked all fluids prior to trip(again forceful fsj habit!) all seemed fine, was maybe less than half a gallon short of water, filled up while running, so I know there were fluids in it. Sorry for such a lengthy one, just trying to cover my bases before I dig into it further. Never really had to wrench on this one, very familiar with my AMC 360, just not my 4.0.
Thanks in advance
Tom

01's you'll find have a problem with the head cracking.
have the head looked at, hope for the best. if its done/cracked, swap in an older one.

X2 - sounds like your head cracked. Lots of info on this on .

Thanks guys, I'll take the head off tomorrow, take it in to get looked at, gonna hope for the best. Till then, I'll do a little more homework, read up on these heads, figure out my options and take it from there. Thanks again.
Tom

Before you pull the head, pressurise the cooling system and stick a pressure gague, or your finger, in the #2 spark plug hole.

~Alex

edit: spelling

If the head is busted that bad, just remove the plug and turn the engine over and the coolant will shoot out.

If it is just the head gasket I would replace the head anyway while it's off with a 92-98 (could be 99, anything that is not a 0331 casting or prior to 92) if you can afford to (head price + manifold/header $150-600 + downpipe ~$60-100 + 30 misc) and don't have the mini cats. You would have to fab a mount for the coil rail as the older heads do not have the mounting bosses.
HTH and good luck

Thank you all for the much needed help. Just wanted to update you all with the bad news and seek further advice. I was in a little bit of a bind when this all happened. I was in the process of moving at the time, had to be in phoenix in 2 weeks and had a very limited budget. Got the head off, had it machined at a local shop, ended up replacing #2 piston ( had small chunk missing off the top), replaced all top-end gaskets and slapped it all back together. Started right up, noticed a bit of a rough idle, engine light eventually lit up, scanned it, ended up with #2 cylinder misfire(same one that had 0 compression as well as a bad piston) Had to move to I could'nt really mess with it. I'm finally settled in at my new job in phoenix so I decided it was time to get the bad news from a local shop. Took it in, compression test showed around 120 psi on both 1 & 3, #2 only had 90. Their diagnosis was a leaking valve on that cylinder, machine shop who did the work claimed they checked the valves and they were fine . Can't tear them a new one since I now live 1600 miles away, so now I'm trying to weigh in my options.

#1 : Have local shop do all the work($450 labor+parts+machineshop work, close to
$1,000 when it's all said and done.

#2 : Found an 06 turn-key 4.0 engine w/40K locally for $1200. Drop it in and go.

#3 : Pull head off again, replace it a brand new after market head for 470+shipping
found on ebay http://cgi.ebay.com/ebaymotors/Parts-Accessories___NEW-4-0-AMC-JEEP-CHRYSLER-0331-CYLINDER-HEAD_W0QQitemZ260253180565QQddnZPartsQ20Q26Q20AccessoriesQQddiZ2811QQcmdZViewItem?hash=item260253180565&

#4 : Find an older head as some of you mentioned earlier and get that one in.

I love this jeep, but have lost alot of confidence in it's relaiblity since this happened. It still runs fine down the road, just has a rough idle at stops, can't run the a/c,( which I found real quick is a necessity out here in Phoenix!) gas mileage is the worst it has every been at the worst time(4.20/gallon!) What would you guys do?
Tom

Send it down the road! The 00 and 01's are the most problematic. Soon your window switch and gauges will go haywire too.

Swapping an older head isn't as easy it sounds with the 2000 and 2001 XJ's as the older heads do not have the brackets for the coil on plug configuration.

Compression sounds a little low on the entire engine, but you just may have some scoring on the cylinder wall of #2, Try an oil additive called Restore to see if it brings the compression back up on #2 enough to keep it going a while longer.

Your rough idle and poor mileage could be the O2 sensor going bad. Silicates in engine coolant destroy O2 sensors, and since you had a leak, I am guessing it went through the exhuast system damaging the O2 sensors, which can make it run rough. Low compression on one cylider makes it idle rough. Have you had CEL code or light?