1997 Jeep ZJ 4.0 Quaker State Defy 10W30 3K

[AmishFury]

my first UOA... their comments make me almost want to reconsider 7500 on the PU that's in there...

 

[Hollow]

Eep. Get that coolant leak fixed and it should be good for another 170k or so.

 

[Donald]

I would run something cheap like Mobil 5000 until you deal with the coolant leak. Hopefully its only a head gasket.

Don't go more than 3K.

This might be of some help.

http://www.cherokeeforum.com/f2/00-01-xj-cracked-cylinder-head-overview-118922/

 

[KCJeep]

Yet another really good UOA for Defy in the 4.0 despite the coolant contamination. Too bad about the coolant that's gonna ruin your high dollar Ultra you'll need to drain it sooner than you'd like no doubt.

Defy is "cheap" too and well proven in the 4.0 I'd suggest you get your leak fixed and just stick with the Defy, you'll be mighty hard pressed to do any better.

 

[SwampSurvivor]

4.0s don't blow head gaskets, they crack the head. Any year of 4.0 is susceptible if overheated enough, just 00-01 do it more often.

 

[Donald]

Originally Posted By: Miller88
4.0s don't blow head gaskets, they crack the head. Any year of 4.0 is susceptible if overheated enough, just 00-01 do it more often.


Is it other heads than the 0331?

 

[SwampSurvivor]

Originally Posted By: Donald
Originally Posted By: Miller88
4.0s don't blow head gaskets, they crack the head. Any year of 4.0 is susceptible if overheated enough, just 00-01 do it more often.


Is it other heads than the 0331?


Yup. The 0331 is more prone to cracking and will crack without overheating. But cracking any of the other heads that came on a 4.0 is very common with overheating.