Originally Posted By: KCJeep
ULTRA!!!!!!
Jeep 4.0's do not like Mobil 1. Nobody is sure why but it tends to produce double to triple the iron numbers in UOA's than virtually any other oil. This tendency has been documented here over and over again. Even the highly regarded here Mobil 1 0w40 does it.
Rather than spend hours and money tearing down engines trying to figure out exactly why, it is simply easier to pick a different oil.
Maxlife. Valvoline WB, Castrol and Rotella tend to produce some of the best looking UOA's in the 4.0, have not seen one on Ultra yet. Maybe Donald will give us one soon enough. I've also had good results with PYB, not much UOA data on it though, a fellow BITOG'er and I are working on that but it takes time.
PU is my vote also.
Using M1 0w30 in the GC during my tests produced more than twice the iron than either Amsoil, VWB, or ST Syn.
ULTRA!!!!!!
Jeep 4.0's do not like Mobil 1. Nobody is sure why but it tends to produce double to triple the iron numbers in UOA's than virtually any other oil. This tendency has been documented here over and over again. Even the highly regarded here Mobil 1 0w40 does it.
Rather than spend hours and money tearing down engines trying to figure out exactly why, it is simply easier to pick a different oil.
Maxlife. Valvoline WB, Castrol and Rotella tend to produce some of the best looking UOA's in the 4.0, have not seen one on Ultra yet. Maybe Donald will give us one soon enough. I've also had good results with PYB, not much UOA data on it though, a fellow BITOG'er and I are working on that but it takes time.
PU is my vote also.
Using M1 0w30 in the GC during my tests produced more than twice the iron than either Amsoil, VWB, or ST Syn.
