Ok guys. I have a 2000 jeep XJ, stock with about 128k miles on it. It's looking like its a cracked head for sure, so my question is do I buy a new, reinforced head, or get a used one from a 84-96?

Any help is appreciated. And thanks for your time

Lake

 

I bought a refurbished head off ebay for $285. Machining quality was good and head was checked for cracks. Put your old rocker gear on and go.

 

Oh and a new casting with improved deck was around $400 shipped.

 

The answer will depend on you budget and risk tolerance. A brand new head from a reputable source will cost between $400-$500. A junk yard unit will probably cost $100-$200 and you could slap it on as is - not recommended, or take it to a machine shop for get it checked out which will cost another $100-$200. I was faced with the same exact decision two years ago and bought a brand new head from Clearwater and never looked back.

 

If it was me this is what I would do as well. You're only spending $100 more at the most when everything is all said and done, and the money is well worth it (depending on the shape of the XJ that is, but if you're planning to fix it, I assume that means you'd be willing to spend $450 on a head)

http://www.cylinder-heads.com/cylind...ms-fits-87-06/

 

Why?
If the head is cracked it takes very few miles to wipe the bearings, a new head is no substitute for a new engine.

 

just got her back from Firestone and they said it's cracked. I have coolent in the oil pan, valve cover and other places coolent shouldn't be.

 

I'm in this camp.

Unless caught VERY early, the coolant will very quickly take out the engine bearings.

Gotta look at the big picture. And usually this involves a rebuild or a salvage yard engine.

I can't count the number of guys who didn't catch this early, swapped in a new and improved head, only to end up realizing that the bearings were gone and so had to go through the repair process once again.

 

Firestone says cracked head, I wouldn't trust them to diagnose a headlight bulb. I've fixed so many of their mistakes it's unreal, I got one of them shut down in the late 80's early 90's. There's no way for them to know it's cracked unless the crack is external or they went in with a borescope which is extremely unlikely, it could be just a gasket.
I've seen MANY vehicles driven with blown head gaskets and cracked heads for a long time with no bearing damage. I've done at least 20 head gaskets and not one had bearing damage. I've yet to hear of one case where water or coolant in the oil wiped out the bottom end. I know it can happen but not right away unless you're driving it like you stole it and it has lots of water/coolant in the oil. One guy I know drove for over a year on a blown head gasket. Didn't change the oil once, just drained the water out occasionally (would start choking the engine with water through the PCV when it got too high) and kept the radiator topped off and drove. It started off as not having the money to fix it then it became an experiment. The car got totaled before the engine died.

 

I would like to steer you in a different direction... There were no 4.0's between 84-86.

Renix heads won't be of any good on your 2000 4.0

91-99 heads could work but u would have to contend with the coil pack mounting holes and make an adapter for the exhaust manifold... Since the 2000 exhaust manifold holes are smaller and sit higher so the ports wouldn't really match.

Obviously 2000/2001 heads are not a good choice...

That leaves us with TUPY heads... Found on 02-04 grand cherokees and 02-06 wranglers.

Direct bolt on without worrying about exhaust ports lining up or mounting holes for the coil packs.

I found a couple of tupy heads, one had 109k miles, and other one was 57k miles on it. Had a machine shop check them for like 40 each.

I would suggest you to read into that. May be much cheaper than buying brand new heads.

 

Thank you. The guy I took it to is looking into that for me. He said a used one would be better for the engine. So I guess whatever he finds should be good. He's priced fairly and knows what he's doing.

 

Make sure it is cracked for a fact, not all 00/01 crack, it could be something else
I got a 2000 XJ with more than 180k on it and running strong.

I know the casting was not the best, but I think it will hold as long as it does not overheat badly.

If cracked, look for another casting, the newer heads are a good choice and bolt on (as I have read), or the one mentioned above from Clearwater

 

Even though if the original head didnt crack, I still wouldn't re use it and then I ll have to spend all my time worrying if it ll crack.

Tupy 0331's provide a peace of mind

 

Here's one for ya- get a 99 head from the jy. Take to machine shop, they drill out the one hole you need for the idler pulley- voilla non crack prone head for 150$.

But also check your main bearings, some people say that "you can drive it for a bit without damage".......no. just do the main bearings, takes all of 2 hours to replace them.

 

u mind elaborating on that?

The ports doesn't line up between earlier heads and the 2000+ exhaust manifolds.

There's no tapped holes on earlier heads to hold the coil packs on it. Mounts ll have to be fabricated.