MBtoRN

I have read that there are problems with the cylinder head castings on the '00-'01 Cherokees. I would like to know if there is an effective repair for this problem.

nujeepguy

my 00 has 169000 and ok but they tell me they can go anytime, no reason. but i guess overheating can do it.
.if it goes you need a new head. the 331 has a flaw in the casting.
its discussed here endlessly.

fb97xj1

Replacement is the only repair. Dont get another original. Get a Clearwater.

BlueRidgeMark

Learn the symptoms, watch for them. If/when it goes, replace it immediately before the coolant can mix with the oil and trash your bearings.

GaMike

MBtoRN, My 00 has 296,000 miles and the head is still fine. I have severely overheated it once. Got lucky I suppose. The three Gentlemen that replied before me gave solid advice.

XJwonders

This!

moparado

As mentioned the only repair is replacement either with a Clearwater cyl. head or a Chrysler 4.0 TUPY head used later than 2001.

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Just throwing this out there.
Tell me if this makes any sense. MY 2000 head with 290k miles never cracked as with many others here. Luck of the card draw or something else?

My 2k was built in late '99. The head was likely cast with fresh new molds.
Could it be the molds for whatever reason and for a lack of a better term 'wore out'
the more they were used?
Multiple different molds some with the potential defect and some without?

XJwonders

It's the design of the head itself that was flawed. Not enough ribbing and thickness of material, not the actual molds itself

moparado

Yep i agree, a design flaw no doubt with no safety factor.
Still..... some '00, 01 heads including my 290k mile head never cracked.
Why some crack while others don't?

Don't know anything about casting cyl. heads but i assume many molds were used in the mfg'ing process to keep pace with production.

Might slight dimensional variations with the specific mold used at some point determine the thickness of the flawed area?
Maybe adding just enough metal to prevent a cracked head?

BlueRidgeMark

Seems reasonable. Add different driving histories, and that would account for the variability, I guess.

Anyway, I think the important things to remember are:

1. It's a known weakness, not a figment of a few people's imagination.
2. It's not an automatic death sentence, either. Plenty of people have no problem.

So drive it, take care of it, and be watchful.

extrashaky

It's probably impossible to know why some crack and others don't, simply because of all the other potential factors. Not only did the head change in 2000, but so did the exhaust manifolds. I wonder if the split design had anything to do with it, causing the head to heat differently from expectations. The split IS right there where the head likes to crack, after all.

Or perhaps it was the way some engines were assembled. Maybe an assembly machine had the torque 1/4 ft. lb. out of spec. Maybe all the ones that crack were assembled on Monday. Maybe all the ones that crack were put together on Bob's shift, and Bob's dumb *** should have been fired years ago. Bob was probably the guy who drilled all those motor mount holes too shallow a few years earlier.

Maybe it would be nice to be able to predict which ones will crack. Maybe it's more interesting for it to be a roll of the dice.

XJwonders

****ing Bob. I hate him so much

BlueRidgeMark

Bob's a union guy, so he retired fat, dumb, and happy years ago, and is living high on the hog.

XJwonders

Haha

moparado

LOL! You don't know how true that is.
If possible, never buy a vehicle assembled on a Monday.
Read on.

Out of HS, i worked full time at a Ford assembly plant.
On Mondays, very high absenteeism from week end partying.
A lot who did show up on Monday were battling hang overs.

In fact later when i quit to go to school, i got a part time job there just on Mondays to fill in for the guys who didn't show up.
We were called Z men and had to learn an assembly line operation in under an hour. Keep in mind, a new full time employee was allowed 3 days to learn an operation.
You guessed it, because of the short learning curve, the Z men performed as bad as those with the hang overs.
The line utility guys who fixed fubars down the line were in high demand on Mondays.