Hi all, Recently purchased an '01 Cherokee with the 4.0. Once I got it home I found out it had the cracked 0331 head. I've replaced the head with an aftermarket replacement. The jeep has 140k miles on it, no knocking, ticks, engine noise etc. It does however have low idle oil pressure when hot verified with a mechanical gauge. (5-8 PSI at idle. 20-35 while at cruising speeds). Even at idle with the low oil pressure all of the rockers are receiving oil and everything sounds pretty quiet. I know there are many posts on many forums about the same issue, just looking for advice until I can decide to sell the car, rebuild it. or drive it till something blows. I know that oil selection alone will not replace engine tolerances or fix damage already done by the coolant/oil contamination. Just looking to buy some time and maybe bump the oil pressure a bit to keep the 'check gauge' light from coming on when the car is idling in traffic. I am currently running a Napa Gold Oil filter stock size, and PYB 10w30. I'm looking to go up a grade in weight to a 40w if possible, not overly concerned about extended oil changes, and cold weather starts aren't a problem as I am in South Carolina and we only get a few days a year of below freezing mornings. Do I: ? 1. Leave the 10w30 PYB in, and drive it with the low hot idle pressure? (oil pressure does not equal flow debate) 2. Bump up to a thicker HM 30w oil like M1 HM which seems to be a thicker 30w when compared to PYB? Would I even notice this change? ([email protected] value of 12.1 vs 10.5) 3. Bump to a 40w HDEO oil like Rotella T6 5w40 or M1 TDT 5w40? These types of oil seem to get alot of praise for the 4.0 with or without oil pressure problems. Not too concerned about spending a few more bucks on these even if i'm not using them to their full OCI potential. 4. Some other combination/oil not mentioned? Would a larger oil filter like a wix 51515 help? How about mixing weights to get something not as thick as say a 40w but thicker than my PYB 10w30? (I have read some previous posts where a thick 40w caused engine knocks and ticks that weren't present before changing to the thicker oil) Thanks!