In my Jeep Cherokee Sport 4.0. It is a 2000 with 121,000 miles. It is fairly new to me and my last oil change I put Mobile One 10W30 high mileage in it with a Mobile filter. Considering Ohio winter, what weight of Mobile One would you recommend as it is due for another change. Thanks much.

 

5w30 or 0w30

 

Also use the same kind of oil every oil change. If you have been using conventional dont switch to synthetic.

 

I thought switching to synthetic was ok? But your not supposed to switch back...

 

I switched to synthetic at 130000 on my 99 and no problems and im at 140000 now

 

Wrong

 

Cause thats helpful. Whats right then? lol

 

I also thought that going synthetic from conventional was fine....in fact, I am sure it is fine.

 

Im using mobile on mine with 330k and the previouse owner used castrole with a synthetic blend and im not having any problems. All i use is mobile on my cars and never had any problems

 

It's about as helpful as it can be. 89Laredo is right, and there isn't really any further explaining it. It's another one of those "synthetic is the devil" myths.

I ran Mobile 1 full syn HM 10w30 for the longest time. No issues. Switched to 10w40 for an oil change (cured a lot of noises and oil consumption, I was very pleased), and then after further research, settled on Rotella T6 full synthetic 5w40 since I live in Shenco. Perfect year round oil with a much smoother and quieter start up/ warm up period.

 

I am just confused on the appropriate weight....I know it is like splitting hairs but nothing is more reassuring than putting in the the oil that has been proven by folks on the forum.

 

The weight should be determined by the ambient (outside) temperature that your XJ is running at.

The weight that somebody is running in Hawaii is NOT the same weight that a person should be using in northern Minnesota where temperatures reach -30 farenheit.

Below is my recommendation for the 4.0 It is also the design engineers recommendation. Good enough for me.

For temperatures PRIMARILY over 60 degrees farenheit, use 10-30

For temperature PRIMARILY under 60 degrees farenheit, use 5-30

 

Yes, you can change back to conventional after using synthetic, after all some oil manufacturers do make "synthetic blends" which is synthetic oil diluted with conventional oil, that's why alot of name brand synthetic oils these days say "Full synthetic" on the bottle as to ensure you that you're not getting some phony baloney blend. that whole thing about not being able to switch back is just an urban legend or myth. hope this clears things up

 

Im always surprised by the amount of stupidity/misinformation when it comes to oil and filters. People need to go spend some time on Bobistheoilguy.com and actually read what they have to say.

 

5W30 = 5 winter and 30 centistokes @ 100degrees c.

I've got books and training from Exxon/Mobil on this.

"The only reason we sell 10w30 or any other 10w, Is because people still buy it."

In other words, you can run 0w30 all year round. It's the last two numbers that tell you how 'thick' the oil is at 100 degrees in centistokes.

While from brand to brand, additives change, 0w30 and 10w30 typically have the same viscosity at operating temp.