Hi all,

This is my first post here. I bought a really clean 2000 xj a few months ago and have about 1,000 miles on it so far. It's my daily driver. I'm fairly certain after some trial and error and digging that the head is cracked, like most 2000s do. I'm losing coolant and can't find a leak. I also see some weeping around the headgasket on the passenger side of the block, of what I believe is oil

My question is, the motor has 183,xxx on it. Has good oil pressure, doesn't overheat, and runs really well. I'm on the fence of putting $600 into a new head, or just running it until it blows and putting $2500 into a brand new motor. I am a hobby mechanic but have friends that have a shop, I'd be doing the labor part either myself or paying friends in food and drinks. I just don't want to put a new head on an old motor and then be out both the money for the new head and the money for a new motor. Any thoughts?

Thanks

 

Putting a head on a old engine is always risky. I’ve seen it go both ways.

But if you do go with a new head and the lower end goes. You can always buy a short block and reuse the head

That’s providing you can find a good reman short block.

 

I put a 2003 Grand Cherokee 4.0 Tupy head from a pick and pull yard and just reseat the valves and installed new valves seals . the head only cost about $75.00 it was clean inside and my engine has about 168.000 miles , runs great doesn't use any oil .

 

Thanks guys. I should have mentioned in my first post that I do have what I believe to be some lifter tick going on, which could be solved by a new head. But it does make me wonder if there is some damage to the lower end of the motor already. I don't have any idea how long the previous owner ran it like this. I just semt for an oil test kit from Blackstone labs. I'd like to see the metal content of that oil.

 

You believe you got an internal coolant leak on head, and the head gasket is leaking oil. Should you keep running? Lets see coolant in the oil, what can go wrong, destroyed bearings? Scored piston skirts, worn rings. Plus you have bad head gasket causing an oil leak externally, maybe internally too. If also internal, i.e. oil getting in combustion chamber, then your catalyst is not long for this world.
Ask if it is worth it to go a bit further as is, I say no, unless you treat this jeep like a Bic lighter, i.e. disposable. and unreliable for long drives.
If your oil pressure is good, i.e. the coolant has not fried the bearings yet, then a new head is prudent. The bottom end of these trucks is very rugged and may give 300K miles. get a new head on there and you may reach 300k miles. So check to confirm oil pressure is good or not, if good then proceed with tear down inspection. pull the head, now you can see the timing chain, the spockets, the cylinder bores, the piston tops, how do they look? drop the pan if you are real concerned, pull a bearing cap for kicks and see the bearing if you are concerned that the oil pressure test missed scored bearings on crank, how is the side to side play on the rods? You can pull the cam too at this point and inspect.
If any of this looks real bad, then you can decide to rebuild the whole engine.

Even if the engine only lasts two more years after the new head, that is less than 1 dollar a day spent over two years for that head.

If you dont want to gamble on a car repair like this, become wealthy.

 

First off, welcome aboard!

Weeping oil along the head gasket on the passenger side isn't a concern. There are no coolant passages on that side and it's just the lifter galleys on that side. The usual culprits for oil leaks are the valve cover, oil filter adapter, and the rear main seal, in that order. While you're waiting on the Blackstone test, have you done a gas test or visually identified a crack through the 710 cap?

 

I have looked through the oil cap but can't see any cracks. The only place I know I am leaking oil is the rear main seal. It's not that bad and is on my project list for this winter.

After giving it some thought, I am going to replace the head and gaskets here in a few weeks when work calms down.

When using a brand new head, should I replace the push rods and rockers and use new ones? The new head will come with valves and springs already installed. Thanks again everyone

 

Before you head down the path of doing the rear main seal, check the valve cover and oil filter adapter. Both can drip off the back and look like the rear main. If the back of the block is oily, it's the valve cover. Cruiser has a nice writeup at http://cruiser54.com/?p=96

 

Thank you all for the replies. I pulled the valve cover this afternoon and the pic is what I found. I am ordering a Clearwater head tomorrow and then the tear down begins. No doubt with all that coolant the head is cracked and no doubt in my mind now it's best to fix it right.

 

Mike Cherokee XJ had 230,000 on it when I had to replace the head. And I actually didn't have to replace the head because I didn't see any water in the oil or have any leaked just had bad compression on cylinder 3 and 4. But to be on the safe side I don't have a lot of money so when I did get enough I just replace the head and I found a good price on one which was $295 rebuild everything. Come to find out the head gasket was blown in between number three and number four cylinder. If you do replace it make sure you get the right casting number off of your head I almost ordered the wrong head until I got to looking for my casting number which was 7120 that was the best casting head they had made throughout the years until they went to the V8. Anyway after I installed the head it runs like a dream no more missing no more problems whatsoever ran fabulous and I also replace the pushrods that wasn't a big deal though did not replace the lifters just push rod. If you find a good price I would replace the head if not have it rebuilt not that much money good luck

 

I replaced heads on a 350 chev and I guess it made more compression and the old rings didn,t like it . Smoked pretty good . It,s a hit and miss. I think do it right the first time and save you more effort down the road . More beer time this way