Hello,

I'm afraid I'm effected by the dreaded cracked head. I have a 2000 XJ with about 174k miles. I'm losing coolant and my oil pressure is around 10psi when hot at idle. I also find milky oil on my cap today. I'm wondering if it's even worth replacing the head at this point? I've been reading a lot of people saying the camshaft bearings could be shot at this point?

I've noticed coolant missing for awhile but, have not found the milky oil until today. The engine has not overheated yet.

Any recommendations?

 

10 psi oil pressure is below spec. 13 psi is the minimum.
That coupled with missing coolant and milky oil, that engine is already or soon to be toast.
Might want to start looking at either a rebuild, boneyard or crate engine.

 

on a cold idle, in the 40s. Does your PSI increase after the head replacement?

 

no, bearings are what increases the PSI, and it appears yours are kapuut.

 

Depends on your finances, technical abilities and garage/tool situation. Ideally you would replace that motor. However, if you're not in a position to swap the motor, you could stop the ongoing damage with a head swap and nurse it along for tens of thousands of additional miles before it gives up. Although 13 psi is the minimum spec, as long as it's not dropping to 0 psi it may still have some life in it.

 

After testing the oil pressure again, I do see it a little above the 10 psi mark. I don't hear any knocking really. I think I'm going to give it a shot, if anything for the experience and hope for the best.

thanks guys

 

you bet, good luck.

 

i w

 

does the pressu

 

This is what happened to my 2001. Almost exactly. The low oil pressure is indicative of bearing failure. The coolant in the oil corrodes the crank bearings and then after awhile there's new places for the oil to go where it shouldn't go. More space and the same amount of oil means lower pressure. This is how I understand the issue at least.

Min had low oil pressure like yours and the bottom end was cooked because of the bearing damage. It's likely your 0331 head was cracked for a long time and slowly coolant has been contaminating the oil and eating the bearings. Have the bottom end rebuilt and get a new non 0331 head. You then have a bulletproof motor.

 

Just wanted to update

I replaced the head myself and running fine for now.
At about 190k now

thanks

 

Try using Shell Rotella T6 5W-40 oil. It's a synthetic diesel oil with additives that help plate bearings.(zddp) It's a bit pricey at $30 per gallon, but Advance Auto has it on sale for $19.99 until Oct 31. Remember it's in gallons, not 5 qt jugs.

 

What replacement head will work as a supplement?

 

You want to make sure whatever replacement head you select is a new heavier duty casting or an OEM TUPY casting from a later model 4.0. Some re-manufactured heads you buy could be from 00/01 heads (non TUPY) and still be prone to cracking.

 

Nice to hear that. Was your oil ever milky/chocolate milk? I've had a really tough time swallowing the idea that coolant is certain death for the bearings.