I think my 2000 has a cracked head!

So I've noticed my coolant has been slowly disappearing over the last month or so. Nothing excessive, but knowing the 0331 head cracking issues, I definitely have been a little worried. Last week I topped it up about a quart after about 2 months of driving.

Today my windshield washer light goes off and I decide to do a quick check under the hood. The usual power steering, transmission, etc. I looked at the coolant overflow and noticed it was down about an inch below the cold level. (This is after driving for about half an hour) So I throw some coolant in it, and decided to check the oil. I pull out the dipstick, and everything looks good. Then it crosses my mind to check the oil filler cap. I open it up, and stuck to the bottom of the cap is exactly what I didn't want to see. Sludge-like chocolate milk. DAMMIT!!

Now I've owned this thing for about a year and a half, and the leaking has only started within the last couple months. I've never, ever overheated it, or even come close. Regardless, there's coolant in my oil, and I'm 99% sure of where it's coming from.

So on to my questions. Is there actually a pre-2000 head that swaps onto my engine without and modifications? Is there an aftermarket one that will do the job? Any idea what a new head costs? (I don't want to replace it with another 0331) How many hours would a shop charge to do this? Is it straight forward enough that someone who's never done one could do it themselves.

I do want to keep this thing for many more years, so I'd like to have this fixed once and for all. Thanks for all your info.

My first post too!!

Dave,

I'd be concerned enough about the sludge to start looking for a new head.

Removing the head off of a 4.0 isn't that difficult of a task. I've tore many heads off of different engines and the 4.0 is by far one of the easiest 'cept it's a little heavy cause of it's length. It can be done by an average mechanic with average tools. I say do a little reading here and go for it, you'll be glad you did.

Just have everything ready.....gaskets, fluid, torque info, etc. and it should take only a couple of hours.

Here's a link for ya...I've never used them but heard a lot of good.....http://www.cylinder-heads.com/Default.asp?

Personally, I wouldn't use another 0331 head even though I have a nice one I just pulled from a yard for cheap. I think a 0630 head would be a better choice.

-Ron

XXX said:

Dave,

I'd be concerned enough about the sludge to start looking for a new head.

Removing the head off of a 4.0 isn't that difficult of a task. I've tore many heads off of different engines and the 4.0 is by far one of the easiest 'cept it's a little heavy cause of it's length. It can be done by an average mechanic with average tools. I say do a little reading here and go for it, you'll be glad you did.

Just have everything ready.....gaskets, fluid, torque info, etc. and it should take only a couple of hours.

Here's a link for ya...I've never used them but heard a lot of good.....http://www.cylinder-heads.com/Default.asp?

Personally, I wouldn't use another 0331 head even though I have a nice one I just pulled from a yard for cheap. I think a 0630 head would be a better choice.

-Ron

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Yeah, I'm checking my options for a new head already. Fortunately, I walk to work so I don't really need to use it until I get it fixed.

I've heard that the 0630 head has different sized exhaust ports? Do you know if I'd have to switch my exhaust manifold to match the head? I know the 2000/2001's have alot more emision sensors and such, and I don't know if I'd be comfortable taking any of that stuff off. Thanks for the input!

I replaced mine last summer, pain in the butt since i did it without any knowledge of replacing it, but it worked and my truck drives much better than it ever did. i did put in there an earlier model, forgot which one, but not a 0331 and the 2 things different are the spark plug rail has bolts that hold it down and with an earlier head there are no holes to bolt into. Mine hasn't fallen off yet but I am going to make a tie down strap to make sure it doesn't fall off. Also there is a coolant sensor in the back that the 0331 head didnt have, so when i had it all together and tested it, it started spewing anti freeze out of it. I just added an earlier sensor in it and no leaks.


I think I got mine from Checker for around 250~ plus the core, was funny looking at their faces when the were looking at my nasty looking cracked head...

James

One time in my quest for 0331 repairs i found a website that had a guys 0331 to 0630 swap in his TJ. Most importantly, it showed the pictures of the bracket he made that screwed in on the valve cover bolts and then over to the rail. Maybe someone who remembers where it is will post the link. Until then i'll keep searching.

kemosabee said:

I replaced mine last summer, pain in the butt since i did it without any knowledge of replacing it, but it worked and my truck drives much better than it ever did. i did put in there an earlier model, forgot which one, but not a 0331 and the 2 things different are the spark plug rail has bolts that hold it down and with an earlier head there are no holes to bolt into. Mine hasn't fallen off yet but I am going to make a tie down strap to make sure it doesn't fall off. Also there is a coolant sensor in the back that the 0331 head didnt have, so when i had it all together and tested it, it started spewing anti freeze out of it. I just added an earlier sensor in it and no leaks.


I think I got mine from Checker for around 250~ plus the core, was funny looking at their faces when the were looking at my nasty looking cracked head...

James

Click to expand...

Did you do it yourself? How long did it take you? Would you mind checking out the casting number next time your poking around under the hood.

So I should just need to jimmy up something to hold the coil pack on, and plug a dummy sensor into the hole? That doesn't sound too bad. Thanks.

cklaus said:

One time in my quest for 0331 repairs i found a website that had a guys 0331 to 0630 swap in his TJ. Most importantly, it showed the pictures of the bracket he made that screwed in on the valve cover bolts and then over to the rail. Maybe someone who remembers where it is will post the link. Until then i'll keep searching.

Click to expand...

Sweet. I'd appreciate that.

I was loving my truck until today.:gonnablow

Dave4.0 said:

Did you do it yourself? How long did it take you? Would you mind checking out the casting number next time your poking around under the hood.

So I should just need to jimmy up something to hold the coil pack on, and plug a dummy sensor into the hole? That doesn't sound too bad. Thanks.

Click to expand...

I did do it myself, took maybe 5-6 hours over a couple days. I did check the paperwork and I did put a #7120 head on it. I actually gave up on it after I put it all back together and it was spewing anti freeze all over the place, so I took it to a mechanic and he filled the whole with a sensor. Doesnt do anything but hold the fluid inside. The mechanic said I did a good job and everything was working and put together correctly. No extra bolts or anything!

With the rail I was just going to get some bendable metal strips and just attach it to some bolts on the head to hold it down. I did it last June and it has not come detached from the plugs and I've driven a whole lot with it like that. But for added security I am going to strap it down.

James

Before going off and swapping the head, the most common reason for slow coolant leak is a bad radiator cap. Buy a nice fresh 16 pound cap and slap it on there. Watch your level.

A pretty much foolproof method of checking out the head is to take it to a mechanic and have him do a hydrocarbons check of the radiator.

As for the oil on the filler cap, I would not worry about that. This is not uncommon and can simply be caused by humidity.

I was worried, but it appears that the search functions still work!

http://www.naxja.org/forum/showthread.php?t=80757&highlight=0331+head
http://www.naxja.org/forum/showthread.php?t=92253&highlight=0331+head

old_man said:

Before going off and swapping the head, the most common reason for slow coolant leak is a bad radiator cap. Buy a nice fresh 16 pound cap and slap it on there. Watch your level.

A pretty much foolproof method of checking out the head is to take it to a mechanic and have him do a hydrocarbons check of the radiator.

As for the oil on the filler cap, I would not worry about that. This is not uncommon and can simply be caused by humidity.

Click to expand...

X2 for the old man. My 2000 had some gunk under the cap and I have no leaks, etc. If it was in the oil it seems like you would see it. Do a pressure test to see if it leaks down. Have the radiator sniffed.

needsrepair said:

X2 for the old man. My 2000 had some gunk under the cap and I have no leaks, etc. If it was in the oil it seems like you would see it. Do a pressure test to see if it leaks down. Have the radiator sniffed.

Click to expand...

Well I'm going to try replacing the rad cap today. I took a flashlight out this morning and I didn't notice any of the sludge inside of the engine. However, there are no leaks under my truck so I'm not convinced it's anything else yet. And it seems to have eaten the coolant I topped it up with yesterday.

I'm also going to take it in for an oil change today and have them take a sample so I can get it analyzed. The lab I use will be able to tell me if there is any coolant present in the oil. Hopefully they can get me the results quickly.

I got the oil analysis results back and it looks like the head is leaking ALOT of coolant into the oil. $20 probably saved my engine.

Looks like I'm shopping for a new head this week.

kemosabee said:

I did do it myself, took maybe 5-6 hours over a couple days. I did check the paperwork and I did put a #7120 head on it. I actually gave up on it after I put it all back together and it was spewing anti freeze all over the place, so I took it to a mechanic and he filled the whole with a sensor. Doesnt do anything but hold the fluid inside. The mechanic said I did a good job and everything was working and put together correctly. No extra bolts or anything!

With the rail I was just going to get some bendable metal strips and just attach it to some bolts on the head to hold it down. I did it last June and it has not come detached from the plugs and I've driven a whole lot with it like that. But for added security I am going to strap it down.

James

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Can you tell me if your old exhaust mainifold bolted up the the older head? I've been hearing alot about how the newer style manifolds will not fit on the older style heads.

Dave4.0 said:

Can you tell me if your old exhaust mainifold bolted up the the older head? I've been hearing alot about how the newer style manifolds will not fit on the older style heads.

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I don't think I have ever heard anything about that. It's a good question though. Are you sure your not thinking HO head to non HO manifold swap?

scoobyxj said:

I don't think I have ever heard anything about that. It's a good question though. Are you sure your not thinking HO head to non HO manifold swap?

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I don't think it's a non HO head. I think they're either the 91-95 or a 96-99 head. I think they were HO heads for those years.

Dave4.0 said:

I don't think it's a non HO head. I think they're either the 91-95 or a 96-99 head. I think they were HO heads for those years.

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Right I realise he is not switching a non HO for a HO head. I was talking about the manifold not mating up correctly issue. I have never heard of it being an issue as long as your staying HO with HO head.

scoobyxj said:

Right I realise he is not switching a non HO for a HO head. I was talking about the manifold not mating up correctly issue. I have never heard of it being an issue as long as your staying HO with HO head.

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Yeah, I'm not too sure. I just remember reading about someone using an 0630 head, and he said the exhaust ports were alot bigger than on the 0331 head.