howellrobby

Ok 2000 sport all stock 4x4 135000...well I have another 0331 cracked head . My oil is fine not milky not raising most of my coolant I'm loosing which is from full to add in about 500 miles I belive to be coming from weeping freeze plug I will post pics. Looked in my oil fill hole when running and indeed saw the crack, very small but there. Runs great no check engine light ect. I do have a rattle when going up very steep incline not in p or n when I rev. Figured hopefully it might b the c clamp on muffler, sounded like engine bay though..It was so loose rusted out I had a leak there. Muffler was shot to so took it off. Plan on replacing soon but now I can't hear the rattle don't know if that was it or if its to dang loud to hear it now.. I'm getting to the point. I'm replacing the head at end of month just bought jeep 5 months ago do u think my engine is pooped and should just start saving for a replacement or get the head put her on and wait it out. I only drive 18 miles a day I know I shouldn't but have no choice. The rattle is making me wonder and oil psi sits at 50 cold drops to 13 14 when real warmed up. What would you do ?? Do u guys think my bearings are ok

howellrobby

Additionally I know spec is minimum 13 psi oil pressure
Just seems low
Can't post pics server error but I know for a fact freeze plug leaking, gonna replace when I do head. First timer here hope I m not biting more than I can chew

md21722

Oil pressure spec is....

13 psi minimum AT IDLE
37 psi minimum at 1600 RPM+

Confirm the oil pressure with a mechanical gauge. Oil pressure sending units can fail and read 80 psi or get old and read low. If the mechanical gauge says 13 psi going down the highway then I would put my money towards replacing the engine because the bearings are shot. Replacing the head is not going to fix an oil pressure problem. Are you saying the rattle is gone?

howellrobby

No just can't hear it , might be gone. But my oil pressure builds back up to 40 @ bout 2000 rpms
It's doesn't stay at 13, only at idle
I'll have to double check tommorow c if I get 37 @ 1600
But I'm pretty sure I do

Firestorm500

Either sell the Jeep as it is, or pull the whole engine out, rebuild the short block, and buy and install a brand new aftermarket head.

Anything else is a waste of time and money.

bigbadon

Simply replace the head ASAP. Your oil pressure is ok which means bearing clearances should be good..... and if motor is quiet you should be fine.

madmanmarty

Fix your exhaust & listen to your motor. If it does not knock....
I would not drive the jeep any further, & replace the head ASAP.
Change oil, add oil additive,100 miles later change oil again.
You may be OK for 10000 or 200000 more miles.

DFlintstone

X2^ Coolant does indeed eat bearings. Maybe change the oil if you can't get to it immediately. Even if the oil looks fine, it's a pretty high stakes game. Fix it!

howellrobby

I'm gonna do the head. Worst case scenario is motor goes and I swap my new head on pull yard 00 motor. Iv seen guys with chocolate milk oil and Chang the head all was good so I guess I'll be fine. The tapping up hills bothers me but I guess I won't know till I get the new muffler if that was it.

howellrobby

yeah I think I will go ahead and Chang oil even though I'm gonna get to it by mid June the head that is. Bummer is if only owned it 4 months so who knows how long it's had this issue

DFlintstone

I hope it didn't have chocolate milk in it before you bought it. I might watch for signs of stop-leak in the coolant. Like MD mentions, checking the actual oil pressure with a gauge might be smart.

Might be a 2000 head will work with earlier blocks. It's the manifolds that don't work on earlier heads if I have that right. Best of luck. June? Eek!

Firestorm500

The only thing a 2000-01 head is good for is a door stop. Maybe a boat anchor.

This OP is in denial like another one on here. Like so many before them that bought 00-01 XJs.

I'm not trying to be cruel or laugh at them. It's just reality.

DFlintstone

Yea, Jeep should have comped people for the original 0331 in my opinion. But then there was TUPY.

I found this somewhere, I can't vouch for it> TUPY heads came on 2002-2004 grand cherokees and 2002-2006 wranglers.

I hear the TUPY foundry mark can be seen through the oil filler.

md21722

As long as the oil pressure meets minimum specs when the engine oil is at operating temperature (takes about 13 miles for my Jeeps) and there are no bottom end noises, replace the head with a 0331 TUPY or a Clearwater. Do NOT use original 2000-2001 XJ heads because the original heads have a very high failure rate. 2002-2006 4.0 heads are 0331 TUPY heads without the defects that made the original 0331 heads crack.

If you go to the junk yard, be sure to take it to the machine shop and have them check it out and surface it. You can search this forum and others and there are probably hundreds of posts about this very issue, what TUPY means, etc. in more detail. When the percentage of coolant in the oil is high enough bearing damage is imminent. Skipping the cylinder head shop and going straight from the top of a junk yard motor the to top of your motor, it might run, but it doesn't mean it was done right.

Most heads need surfacing to take out any warpage. Many 4.0 engines have pitted valve seats, #1 and #6 are the ones that usually show problems first. The head shop can fix both and give you back something that you can run for the next 150,000+ miles for $135-300 depending on shop and area.

Use new head bolts. Head gasket, manifold gasket, thermostat gasket, are mandatory. Valve cover gasket only if it needs it.

howellrobby

I appreciate the sound advice. My motor runs great,oil pressure is min spec. No knocks I belive my noise under load was either pre detonation or leaky muffler . Can't hear it now. So I have read all the write ups on the swap plan on going with Clearwater head I'm gonna replace everything I can afford to while I'm doing so. I was having second thoughts but cannot bare to just throw my hands in the air.
It's my first jeep and I'm gonna do what I have to. Even if down the road I must replace engine. It's worth it to me