2000 Cracked Head?

Ok. I know this was discussed about a month ago here http://www.naxja.org/forum/showthread.php?t=50045&highlight=2000+oil but rather than revive that thread I have a few different questions I will post here. The Jeep is a 2000 4.0 whith 69,500 miles and the 2000 is apparently plagued with junk heads. I have taken off the oil cap and looked for the leaky green with flashlight and didnt see any coolant but I have noticed a little bubble (where the red arrow is pointing in photo) a few times a minute, maybe. While I havent noticed coolant in the oil while changing oil I do possibly, maybe, notice oil in coolant (if that is possible). Im not sure if oil is in the coolant which was last flushed this past december or if it's just a little rusty. You can see from the photo that my warm idle is right around 500 rpm and my warm idle oil pressure hovers right around 20. What do you think? Does the little bubble mean I have a cracked head? the oil cap is a little slimy brown but... Im just not sure. Can the oil go into coolant rather than vise versa? If I do have a cracked head what should I do? It is not under any warranty.

From all the info I've gleaned from the two threads you need to replace your head right away. The longer you wait the more damage you do to the bearings. I'm rebuilding my daughters engine right now because she drove for awhile with the engine heating up and having to add coolant every once in awhile. Changing a head can be done by a novice with a good manual and a good set of tools. Easier and less expensive than an long block.

ok. how long did it take you to do this and what was the cost? Im seriously thinking it might be a good idea if I actually do have this problem. in the meantime would changing my oil every 2,000 rather than 3 be a help?

if coolant is not disappearing and oil is not disappearing, and you're not finding any of one in the other, leave it alone.

if you drained your coolant and there was no obvious oil what made you look in your oil cap with the engine running.

its not overheating, nor have you noticed any adverse effects right.?

if it aint broke dont fix it. 20lbs is adequate at idle, if you want higher put in thicker oil.

stop wishing for things to go wrong with your heep, just be patient, the pain will come.

goodburbon said:

if coolant is not disappearing and oil is not disappearing, and you're not finding any of one in the other, leave it alone.

if you drained your coolant and there was no obvious oil what made you look in your oil cap with the engine running.

its not overheating, nor have you noticed any adverse effects right.?

if it aint broke dont fix it. 20lbs is adequate at idle, if you want higher put in thicker oil.

stop wishing for things to go wrong with your heep, just be patient, the pain will come.

Click to expand...

When I bought the Jeep 8 months ago it was very low on coolant and there was all kinds of crap in there, which tells me it probably wasnt maintained all that well.

It is not overheating, but my last XJ (a 94) would be 40lbs at warm idle and 70lbs cruising. This is what made me intially wary and then when I started hearing about the 0331 Head problems I decided to check it out.

I am not wishing to for things to go wrong even if I do seem a little overconcerned.

Thanks for the feedback.

There can be other problems that cause cooling fluid loss. The first thing I think of when I have this problem is the radiator cap. Don't laugh, many of the used cars I've owned had this problem. Radiator caps last about 3-5 years. Then the spring looses its tension and it doesn't hold the proper PSI rating. I agree with the others, if no coolant detected in the oil, no problem. I would flush the coolant system, put on new hoses and a new 'Robert Shaw' or Mr. Gasket Hi-Flow thermostat and see what happens. If there's oil in the coolant, then thats probably a blow head gasket or warped head.
Tom