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XJ Ask the Question Thread
99, 4.0 w/ 170k on it. Running rotella 15-40 now, but Vermont gets cold. It's usually around 32* leading up to January, then can be as cold as -20* or more when the cold snap hits sometime in February. I was thinking switching to rotella 10-30 or 10-40 synthetic for the coming months, but thoughts and opinions on switching to synthetic? All good? A waste? Should I continue to run synthetic in summer? Thanks fellas.
Senior Member
Joined: Dec 2011
Posts: 669
Likes: 0
From: Central Arkansas
Year: 1996
Model: Cherokee
Engine: 4.0L
99, 4.0 w/ 170k on it. Running rotella 15-40 now, but Vermont gets cold. It's usually around 32* leading up to January, then can be as cold as -20* or more when the cold snap hits sometime in February. I was thinking switching to rotella 10-30 or 10-40 synthetic for the coming months, but thoughts and opinions on switching to synthetic? All good? A waste? Should I continue to run synthetic in summer? Thanks fellas.
Won't do diesel oil, dunno if that was a crack based off the fact I managed to grab a container of diesel oil earlier today, or a serious comment, but I'm gonna pass on the T6, too.. :/
Senior Member
Joined: Dec 2011
Posts: 669
Likes: 0
From: Central Arkansas
Year: 1996
Model: Cherokee
Engine: 4.0L
Ummm... You're running Rotella 15w40. That's diesel oil. How would I know what you did earlier today? You asked about switching from Rotella to synthetic, I gave you two options in a similar class to what you are using now. And the M1 TDT is a great oil for the 4.0.
Last edited by cranesrule; Oct 19, 2013 at 09:40 PM.
Well.. Allow me to show my ignorance in all of its blazing glory. So I follow that with 1- thanks for correcting me, I surprise even myself sometimes, unfortunately not always in my favor 2- I posted in "what did you do with your cherokee today" thread about changing my oil, I thought maybe you saw it and based your comment off that. Sorry, wasn't tryin to be rude! 3- thanks for the info on the Mobil1, I'll have to look into it. Thanks again and I really wasn't trying to sound disrespectful. Haha, always hard to tell the inflections thru the net, that and there's no lack of wisenheimers on here..
Last edited by VTJeep; Oct 19, 2013 at 10:03 PM.
Senior Member
Joined: Dec 2011
Posts: 669
Likes: 0
From: Central Arkansas
Year: 1996
Model: Cherokee
Engine: 4.0L
Well.. Allow me to show my ignorance in all of its blazing glory. So I follow that with 1- thanks for correcting me, I surprise even myself sometimes, unfortunately not always in my favor 2- I posted in "what did you do with your cherokee today" thread about changing my oil, I thought maybe you saw it and that based your comment off that. Sorry, wasn't tryin to be rude! 3- thanks for the info on the Mobil1, I'll have to look into it. Thanks again and I really wasn't trying to sound disrespectful. Haha, always hard to tell the inflections thru the net, that and there's no lack of wisenheimers on here..
I'm a huge fan of that oil for almost every application where it's weight appropriate. I use it in my 4.0 I6 Jeep, 4.0 V6 Frontier, 20HP Honda V Twin mower, 12HP Yamaha generator... And it will soon be going in my 115HP Mercury four stroke outboard.
Herp Derp Jerp

Joined: Nov 2011
Posts: 18,251
Likes: 17
From: Parham, ON
Year: 1999
Model: Cherokee
Engine: 4.0L OBD-II
Mobil1 TDT 5w40 is ****ing expensive. Shell Rotella T6 5w40 is a better oil for less cost. IIRC Rotella T6 and Mobil Delvac 5w40s actually give the best UOAs in the 4.0L.
Guess I'm glad I asked. Rather look foolish and know as opposed to some sort of quiet r-tard wisdom, or something.. You see what I'm driving at..
Guess I shoulda changed my oil after all..
Guess I shoulda changed my oil after all..
Senior Member
Joined: Aug 2012
Posts: 583
Likes: 0
From: Clear Lake, TX
Year: 1999 Jeep Cherokee
Model: Cherokee
Engine: 4.0
I pulled the manifold and found all this junk in the intake manifold and in the intakes on the block. I can see a decent amount of the same build up on the valves in the block. Will Sea Foam help get rid of the buildup on the valves?
Last edited by Houston Kid; Oct 20, 2013 at 06:48 PM.
CF Veteran
Joined: Sep 2012
Posts: 1,289
Likes: 0
From: Springfield Virginia
Year: 1998
Model: Cherokee
Engine: 4.0
I'm thinking about bedlining some more of my jeep. Either doing the whole rear quarters or I was thinking about doing the entire side of it below the halfway crease like this jeep

How do you guys think it would look on mine?


The main reason I'd do it all would be *******s at my school drawing stuff while it's muddy so it's real scratched with dicks and "*****" written into it

How do you guys think it would look on mine?


The main reason I'd do it all would be *******s at my school drawing stuff while it's muddy so it's real scratched with dicks and "*****" written into it
CF Veteran
Joined: Sep 2011
Posts: 10,447
Likes: 0
From: Frederick, MD
Year: 1989
Model: Cherokee
Engine: 4.0
I'm thinking about bedlining some more of my jeep. Either doing the whole rear quarters or I was thinking about doing the entire side of it below the halfway crease like this jeep
How do you guys think it would look on mine?
The main reason I'd do it all would be *******s at my school drawing stuff while it's muddy so it's real scratched with dicks and "*****" written into it
How do you guys think it would look on mine?
The main reason I'd do it all would be *******s at my school drawing stuff while it's muddy so it's real scratched with dicks and "*****" written into it
haha, oh high school.. yeah man, do it! the purple/black look will be nice. Maybe spring for paintable bed liner. generally more expensive, but it has better properties for holding up to UV rays etc..
CF Veteran
Joined: Sep 2012
Posts: 1,289
Likes: 0
From: Springfield Virginia
Year: 1998
Model: Cherokee
Engine: 4.0
I just used rustoleum spray on bedliner for the bottom portion and it's not to bad. You think I should use the actual foam roal on type?
Last edited by ThatPurpleXJ; Oct 20, 2013 at 11:27 AM.




