Okay, thanks for all of the advice. I stayed with 5W30 and started running B12 fuel system cleaner in Th' Beast. The 5W30 is a full synthetic. I have a friend that is an ASE certified mechanic. His advice is to use the brand plugs that the engine was designed around. He also said that newer engines need to run a 5W weight oil. He works on everything but Jeep is his specialty. And as far as oil/filter changes, I always do that. Just not sure how the previous owner cared for her. I am now facing a high idle problem after replacing the IAC sensor. Looking into the TPS as maybe the cause. I don't bother my mechanic friend because he has done so much for me in the past. Trying to make it on my own. So if anyone has any input into the high idle problem I would appreciate it. The IAC sensor fixed a lot of problems including acceleration power. Idle was low but now is too high. ??? Im sure there is an adjustment on the TPS. Thanks..... Vinny

 

5w40 rote tells diesel oil with 214k miles, 35 psi oil pressure at hot idle, runs like a top.

 

Last oil change I switched to rotella t6. Really liking it so far. Lots of good detergents and hold good oil pressure.

 

I would avoid fram oil filters they are junk materials..Mopar,motor craft (Fl-1A) if u want higher capacity ,or wix are better choices.Heres a pic to show the insides as u see the three i recommend are built with metal ends and better quality ,if u look at fram cheap materials,paper ends the paper always has a weird residue on it..

 

I have been using Mobil One High Mileage most of the year. In the Winter I have some regular Mobile One and Mobile One extended in storage. Once used up I'll probably go with High Mileage Mobil One year around.

I've thought about switching to another brand oil. There are other good brand oils out their but I'm not as familiar with them as Mobil One, that I have been using for more than a decade.

High mileage engine oils such as Mobile One is thicker and includes seal conditioners and other additives better suited for high mileage engines. (Mobil One High mileage has a higher zinc content than regular mobil one)

I found a good deal on a case of Mobil One filters and a case of Amsoil oil filters. So I'm using them as their designed more specifically for synthetic oils.

I try to change at around very ~4 to ~5 thousand miles or less when off-road, towing, etc.

 

I started running rotella t5 10-30 in the 3 that are driven and after a few changes it stayed cleaner longer. Obviously cleaned some crap out. I have noticed though that the engine will get a little noisy around the change interval. Unfortunately they did start seeping more oil after also. They are an 01 with 195k, 98 with 214k and 98 with 163k. Ran castrol gtx high mileage in the wj when I had it and it seemed to make the lower end much noisier. Won't ever use that again. The one time I had the shop in town change my oil they put in 5-30. I think that may be spec. Definitely could hear a difference with that stuff. Oil is such an over debated topic I decided to try the rotella and am happy with it and it's fair priced. And if it's good enough for heavy equipment then it should be ok for a little 4.0.

 

So you bought an old, used up Cherokee. Have put a lot of money into her (guess moving out of N Georgia is on hold since you spent your money on a Jeep) ...Th' beast, huh? But an idiot mechanic ruined her? Why would you buy it then? Were you drunk when you bought it? You need all the advice you can get...No one cares what your Malibu 2.4 used, that is just dumb!!! Chevy...Jeep, not even close! CHRYSLER would have been a better comparison. B12? Yeah just throw some chemical in there because that is gonna fix it!!! Thanks for all the great advice that your ASE certified mechanic gave you but you don't wanna ask him anything more because you have used up THAT friend. Thank goodness Jeeps are his specialty...too bad they are not your specialty. Making it on your own, laughable to say the least. High idle problem? Well you only had that when you dropped a viagra, maybe Th' Beast needs one as well. Your welcome.

 

 

I didn't read through the whole thread, but you are gonna get a million different answers to this question. Also, I did catch the post about the fram oil filter. Don't, and I repeat, DO NOT use a fram oil filter.

EDIT: Just realized this is an old thread brought back from the dead. However, please don't use fram oil filters.

 

I would like to know if I should use the new mobile 1 1 year annually 20,000 miles pertection for my 1999 jeep grand cherokee leredo 4x4 v8 4.7L. I want to use also the same oil for the oil filer models that would be the mobile 1 annually 20,000 miles pertection. Please let me know as soon as possible I need recommended likes. Ps it's is a ultra full synthetic but they only come in a 5w 30 and lower types please let me know soon thanks guys

 

I personally wouldn't use it. I'm not saying it's a bad oil, but only changing your oil once a year doesn't sit well with me. But I also put a good 15k on my XJ a year.

Also, as far as I know, that stuff is new, so I don't think anyone has much experience with it. Just grab some Mobil 1 high mileage, or Rotella T6 5w-40, and a good filter (mobil 1, Wix, Mopar, etc.) and change your oil every 3 to 5k miles.

 

I noticed oil diminish when i drive it about 7000 to 8000

 

What's the difference between T4 and T5?

 

I am using Pennzoil Platinum 10W-30 in my jeep, which can give an awesome result. This is the finest synthetic oil that can give you protection from friction. This engine oil keeps piston up to 45% cleaner and helps to protect the engine from loss of power. This one is the perfect oil for your Jeep.

 

Yeah... old thread.... but T4 is dino oil and T5 is a blend. I run T5.