PatHenry

Agree - I had to replace my exhaust manifold just shy of 2 years ago and was far more worried about doing the job than was necessary. If you've done a water pump, you can probably swap a head on the AMC tractor engine in your XJ.

You'll want a good torque wrench (by good I mean accurate and of decent quality - it doesn't have to be a Snap-on, but I'd be leery about an Autozone special or a Harbor Freight cheapo) and a good set of socket extensions and wobbly bits (the u-joint ones) and wrenches. You can get a nice set of long length wrenches at Harbor Freight for like $20. Their solid hand tools, extensions, combo wrenches, etc. are a great value and more than good enough for the average DIY'er.

Visit http://cruiser54.com/?page_id=365 and get the FSM (if you're not familiar - Factory Service Manual - it's what the dealer mechanics use for reference and is like a Haynes/Chilton manual on steroids) for the 00 XJ. Tons of info and all the torque specs/tightening order/diagnostic info you could ever want.

PatHenry

Crank bearings are the common failure when an engine has run for too long with coolant in the oil. I personally don't believe that in your situation (based on how you've described it) that you have run it too long.

Take some pictures of the block once the head is off and there's a lot that folks around here can tell you just by getting a good visual look at the cylinder walls and piston faces.

The 4.0 is a VERY durable engine - the vast majority of folks that experience the head defect need only replace the head. Many have done so and driven many years and many miles without further trouble.

PatHenry

I was even luckier on my 00 TJ. 302k miles without a crack and AFAIK the engine still runs flawlessly.

bluejeep2001

Hey did those links I sent you work out?

Tony the Liger

Hey everyone. Long overdue update.

After the busiest semester of my life, I finally had time to tear down my engine a couple weekends ago. Took a full Saturday and a lot of hand-wringing, but my cousin and I actually managed to pull the original head. We're going back in later today or tomorrow to get everything as clean as we can, and if all goes well we'll reassemble everything sometime this week. I'm installing a new Clearwater head (and new gaskets, obviously).

So, a couple of questions before we proceed:

1. The ports where the push rods go (sorry, I don't know the name) are pretty nasty with oily, sludgy gunk. Aside from sticking my finger or a long, thin stick or something down in there and scraping away as much of that stuff as possible, is there any way to get those spaces clean? I've read the extensive cylinder head replacement thread on this board and followed it closely, including covering the cylinders with two-stroke oil before scraping away the old gasket crud, but I didn't see anything about those ports. If cleaning those ports isn't a concern, should I at least stuff a rag down in them or something to keep more crud from falling in while we brush the top of the block? Some friends have said yes, and others have said not to worry about it because "all that stuff's just going to go to your oil pan anyway."

2. I'm not in the business of adding problems that aren't already there, but while I have this thing torn down, should I replace the freeze plugs? They appear to be fine, but I don't want to have to do this again.

3. Any other critical steps, replacements, etc. any of you would recommend while the engine is torn down?

Thanks for everything along the way. Looking forward to hearing from some of you.

Tony the Liger

I'll attach pics later this evening.

dave1123

You should keep as much crap out of the oil pan as possible since small particles can lock up an oil pump! You can use a shop vac with a small 1/2" copper water pipe in the end of the hose to pull most of the junk out, using the pipe as a scrapper. If you don't want to mess up your shop vac, you can build one using a piece of 1/8" copper tube, bent into a u-shape and soldered into the side of that 1/2" copper pipe, using your air supply to power it. use a 5/8" heater hose on the discharge end or it will be all over your face!

Of course, pulling the oil pan and cleaning it is the best way to go.

WORD OF CAUTION with that "Clearwater" head! There is a small pipe plug on top next to the valve cover above the #5 cylinder that is for a rear temp sensor. Make sure that plug is sealed and tight! Mine was painted black and I didn't see it. The head started leaking coolant 2 days after installing it! I freaked out!!

Tony the Liger

Figured as much.

Good call on the copper pipe. I'll give that a shot.

dave1123

Re-read the last post about the pipe plug. I was editing while you were replying.

Tony the Liger

First I've heard of this. Thank you.

You said for "a" rear temp sensor and not "the." Does this mean mine may or may not have that sensor? And if there's no sensor, what'd you use to plug/seal the spot on the head?

dave1123

It's a small pipe plug that only needs pipe dope or teflon tape to seal. It's there so the head can be used on jeeps that have that rear sensor, like TJ's I've been told. If you only have that sensor, the one by the thermostat needs a 1/2" pipe plug, or maybe it's a 3/4" IDK. "Clearwater" supplies the head with that small plug, but mine was painted over and not tight enough.

Tony the Liger

10-4. Thanks again.

I'd have never known and would probably have had this thing on Craigslist for parts by next week if I'd gotten it back together and discovered a "leak" from a brand new head.

dave1123

Another thing. The front-most head bolt on the driver's side shouldn't be torqued more than 100 ft/lbs. It also needs thread sealer because it's the only bolt that is threaded into the water jacket and lacks the support of metal in the bottom of the hole. I've heard horror stories of block decks that have cracked because of over-torquing that bolt, although I don't necessarily believe that.

Tony the Liger

Yeah, I've got the torque specs in the Haynes manual. If memory serves, that bolt's 100 and all the others are 110.

Do you have an opinion on the freeze plugs? Mine look fine, best I can tell, but should I go ahead and replace them with brass while I'm there?

dave1123

My opinion? My 2000 WJ 4.0 had 253K miles on it and were fine when I pulled the engine for a cracked piston skirt. If they are not rusty, throw some paint on them. The one to watch is the one on the back of the head, but since your getting a new head, that's kinda moot. There's one behind the flexplate. but that's pretty well protected. "If it ain't broke, don't fix it!" You'll need your money for other things! LOL!