Which oil to use? - JeepForum.com
Search  
Sign Up   Today's Posts
User: Pass: Remember?
Advertise Here
Jeep Home Jeep Forum Jeep Classifieds Jeep Registry JeepSpace Jeep Reviews Jeep Gallery Jeep Clubs Jeep Groups Jeep Videos Jeep Events Jeep Articles
Go Back JeepForum.com > Models > Jeep Grand Cherokee & Commander Forums > WJ Grand Cherokee Forum > Which oil to use?

Huge Soft top SaleAdvance Adapters SYE KitsCurrie Antirock, Currectlync & Lift Kits on Sale!

Reply
Unread 07-07-2013, 06:14 PM   #1
charleswilson90
Registered User
2003 WJ 
 
Join Date: Nov 2012
Location: Colorado Springs, Colorado
Posts: 24
Which oil to use?

This has been beaten up and down on this forum but I just wanted to put it out there that I have been spending nearly $40 an oil change for the past 50k miles on my 4.0 for Mobil 1 high mileage synthetic. I just switched to Rotella T5, this Jeep sounds brand new! And it is half the price! Now if I could get Mobil to cut me a check for all that wasted money...

charleswilson90 is offline   Reply With Quote Quick reply to this message
Unread 07-07-2013, 06:28 PM   #2
Jer-Bear
Registered User
2002 WJ 
 
Join Date: Mar 2013
Location: , Texas
Posts: 491
I wouldn't use a pure synthetic. If you've run conventional it's whole life, switching can dry out rubber. Rear and front main seal, etc.
__________________
/ 2002 WJ 4.7 H.O. / Flowmaster 50 SUV / Magnaflow Cats / Rocking that 2WD! /
Jer-Bear is offline   Reply With Quote Quick reply to this message
Unread 07-07-2013, 07:12 PM   #3
rcwj04
Senior Member
 
rcwj04's Avatar
2004 WJ 
 
Join Date: Mar 2012
Location: Flemington, New Jersey
Posts: 835
^um..........
__________________




Quote:
You forget that most members here don't own a crystal ball to tell you exactly what your problem is, specially with bad pictures that don't say/show much of anything... -Jacko84

Just a 19 year old kid with a Jeep, and broke because of it, and loving every moment.
---------------------------------------------------------------
2004 WJ Laredo 4.0 116k
2" BDS coils & Bilstein 5100's | Addco rear swaybar with energy bushings |
K&N FIPK | glasspack | plasti-dipped badges | 17" moabs | HID's, 245/65/17 Cooper Discover AT3 | Rola rack | Fawkes stand alone shackle tabs | Bed lined interior (what a pain that was)
rcwj04 is offline   Reply With Quote Quick reply to this message
Unread 07-07-2013, 07:21 PM   #4
pinky2252s
Registered User
2001 WJ 
 
Join Date: Oct 2011
Location: Broomfield, Colorado
Posts: 1,825
Quote:
Originally Posted by Jer-Bear View Post
I wouldn't use a pure synthetic. If you've run conventional it's whole life, switching can dry out rubber. Rear and front main seal, etc.
Hes been running a synthetic for 50k. Plus I have never heard of synthetic oils drying anything out.
__________________
Is it broken?

Colorado Jeep Club Member #2252
2001 Laredo, 2004 Special Edition
pinky2252s is offline   Reply With Quote Quick reply to this message
Unread 07-07-2013, 08:09 PM   #5
jimh989
Registered User
2002 WJ 
 
Join Date: Nov 2009
Location: Midland, Michigan
Posts: 42
Really I don't think I would worry about it if you keep it changed all the time. Before I sold my i6 ZJ with 235k on it I ran straight 30w for two years. Well i the summer. 10w40 winter. I am thinking it may be time to switch the v8 wj from 5w30 to 10w30. It's at like 113k, I may give it a few more mile considering its alum. Heads....
Just keep it changed, my two cents
jimh989 is offline   Reply With Quote Quick reply to this message
Unread 07-07-2013, 08:15 PM   #6
coloradowjowner
Registered User
2002 WJ 
 
Join Date: Jan 2013
Location: Fort Collins, Colorado
Posts: 207
Quote:
Originally Posted by rcwj04
^um..........
x2
coloradowjowner is offline   Reply With Quote Quick reply to this message
Unread 07-07-2013, 09:02 PM   #7
charleswilson90
Registered User
2003 WJ 
 
Join Date: Nov 2012
Location: Colorado Springs, Colorado
Posts: 24
Yeah I change it every 3k. I havent ever heard of synthetic drying gaskets? I was just posting this because of all the threads I read on here talking about which oil is best in the 4.0 and I was saying I'm on team Rotella is all. Cheaper, runs better. I guess I will see if it goes another 100k on the cheap stuff.
charleswilson90 is offline   Reply With Quote Quick reply to this message
Unread 07-07-2013, 09:56 PM   #8
Planetcat
Registered User
2004 WJ 
 
Join Date: Jan 2010
Location: West of the Mississippi
Posts: 1,410
How would we know if synthetic would be ok or not without the OP even stating what the mileage is on his rig?
__________________
2004 WJ 4.7L, 1959 CJ-5, 1990 XJ Limited, 1996 XJ (sold), 1989 YJ Wrangler 4.2L (Sold)
Planetcat is offline   Reply With Quote Quick reply to this message
Unread 07-07-2013, 10:44 PM   #9
Jrboarder27
Registered User
2000 WJ 
 
Join Date: Oct 2011
Location: Boulder, Colorado
Posts: 1,030
Quote:
Originally Posted by charleswilson90 View Post
This has been beaten up and down on this forum but I just wanted to put it out there that I have been spending nearly $40 an oil change for the past 50k miles on my 4.0 for Mobil 1 high mileage synthetic. I just switched to Rotella T5, this Jeep sounds brand new! And it is half the price! Now if I could get Mobil to cut me a check for all that wasted money...
How do you know Mobil 1 was a waste maybe its what has been keeping your jeep running so well. I can get six quarts of Mobil 1at wally world for under 30 bucks
Jrboarder27 is offline   Reply With Quote Quick reply to this message
Unread 07-07-2013, 10:46 PM   #10
Jer-Bear
Registered User
2002 WJ 
 
Join Date: Mar 2013
Location: , Texas
Posts: 491
Quote:
Originally Posted by charleswilson90 View Post
Yeah I change it every 3k. I havent ever heard of synthetic drying gaskets? I was just posting this because of all the threads I read on here talking about which oil is best in the 4.0 and I was saying I'm on team Rotella is all. Cheaper, runs better. I guess I will see if it goes another 100k on the cheap stuff.
It may or may not be true, but I've heard people say that after running conventional for a long time and switching can do this. It could be that it slips past things more, I don't know. I'm not even comfortable with a synthetic blend in mine.
__________________
/ 2002 WJ 4.7 H.O. / Flowmaster 50 SUV / Magnaflow Cats / Rocking that 2WD! /
Jer-Bear is offline   Reply With Quote Quick reply to this message
Unread 07-08-2013, 03:48 AM   #11
SteelBlue_WJ
Web Wheeler
 
SteelBlue_WJ's Avatar
 
Join Date: Feb 2006
Location: Tempe, Arizona
Posts: 2,108
Quote:
Originally Posted by Jer-Bear View Post
It may or may not be true, but I've heard people say that after running conventional for a long time and switching can do this. It could be that it slips past things more, I don't know. I'm not even comfortable with a synthetic blend in mine.
This has actually happened to me... switched to full syn after 130K on conventional only. started having leaks and was recommended by my buddy who was a jeep service tech to switch back to conventional and all leaks stopped but i suspect my valve seals may need replacement now after that. I was told general rule of thumb is if it's been run on only conventional and it has at least x amount of miles on it, its better to stay on it or a blend, but not full syn.
__________________
Bobby

2001 Steel Blue WJ Laredo SA 4x4, 3.5" lift, Apperance Package with factory Laredo Steel Blue cladding/leather
Conferr Roof Basket with custom Randy Ellis Design light cage, WAAG grille guard and Hella lots of 500 lights


2004 Wrangler Sport, 2.5" and 31's, nothing special

"For all sad words of tongue and pen, the saddest are these, 'It might have been.' "
John Greenleaf Whittier
SteelBlue_WJ is online now   Reply With Quote Quick reply to this message
Unread 07-08-2013, 07:59 AM   #12
briandor
Registered User
2004 WJ 
 
Join Date: Feb 2013
Location: Sinking Spring, Pa
Posts: 196
Quote:
Originally Posted by SteelBlue_WJ View Post
This has actually happened to me... switched to full syn after 130K on conventional only. started having leaks and was recommended by my buddy who was a jeep service tech to switch back to conventional and all leaks stopped but i suspect my valve seals may need replacement now after that. I was told general rule of thumb is if it's been run on only conventional and it has at least x amount of miles on it, its better to stay on it or a blend, but not full syn.
What you're actually seeing is not something being caused by the synthetic oil but something that already existed before putting the synthetic oil in. Synthetic oil is engineered to have smaller molecules. This is what makes it smoother and better at lubrication but it also gives it the effect of being thinner.

Rubber seals by their nature gradually break down over time as they shrink and harden and even crack. With a conventional oil it will take longer to see the effects of this (leaks) then it would with synthetic because the molecules of conventional oil are bigger and therefore harder to fit through the cracks and gaps in the aging seals. Now take those same aging seals and put synthetic in and the smaller molecules are now able to squeeze through the gaps and you have leaks. A good way to think of this would be to picture Jello on top of a window screen. For the most part it will not leak through the screen but as the Jello begins to warm and thin it will gradually start oozing through. Obviously leaks aren't good but they synthetic is also still providing it's benefit as well which is better lubrication.

I would tend to agree with remaining with conventional oil on an engine that has high mileage and always used conventional. At that point you're already passed the point where the benefits of synthetic would have much effect in engine life and really the synthetic would simply point out the wear and aging that has already occurred with an effect as you saw with additional leaks.

BTW, synthetic isn't going to cause any damage. Your valve seals will be in whatever state of wear they were before you put synthetic in. The synthetic doesn't cause seals to dry and crack or shrink any more than conventional would, which is to say it doesn't at all. Air and heat are actually what causes rubber seals to dry and crack. Oil of any kind actually helps to prevent and delay this.

As a side synthetic oil isn't really synthetic at all any more. Originally created from a purely synthetic base stock what is sold as full synthetic oil today is in fact conventional oil that has undergone a process called hydrocracking.

http://en.wikipedia.org/wiki/Synthetic_oil
briandor is offline   Reply With Quote Quick reply to this message
Unread 07-08-2013, 09:02 AM   #13
Jer-Bear
Registered User
2002 WJ 
 
Join Date: Mar 2013
Location: , Texas
Posts: 491
Quote:
Originally Posted by briandor View Post

What you're actually seeing is not something being caused by the synthetic oil but something that already existed before putting the synthetic oil in. Synthetic oil is engineered to have smaller molecules. This is what makes it smoother and better at lubrication but it also gives it the effect of being thinner.

Rubber seals by their nature gradually break down over time as they shrink and harden and even crack. With a conventional oil it will take longer to see the effects of this (leaks) then it would with synthetic because the molecules of conventional oil are bigger and therefore harder to fit through the cracks and gaps in the aging seals. Now take those same aging seals and put synthetic in and the smaller molecules are now able to squeeze through the gaps and you have leaks. A good way to think of this would be to picture Jello on top of a window screen. For the most part it will not leak through the screen but as the Jello begins to warm and thin it will gradually start oozing through. Obviously leaks aren't good but they synthetic is also still providing it's benefit as well which is better lubrication.

I would tend to agree with remaining with conventional oil on an engine that has high mileage and always used conventional. At that point you're already passed the point where the benefits of synthetic would have much effect in engine life and really the synthetic would simply point out the wear and aging that has already occurred with an effect as you saw with additional leaks.

BTW, synthetic isn't going to cause any damage. Your valve seals will be in whatever state of wear they were before you put synthetic in. The synthetic doesn't cause seals to dry and crack or shrink any more than conventional would, which is to say it doesn't at all. Air and heat are actually what causes rubber seals to dry and crack. Oil of any kind actually helps to prevent and delay this.

As a side synthetic oil isn't really synthetic at all any more. Originally created from a purely synthetic base stock what is sold as full synthetic oil today is in fact conventional oil that has undergone a process called hydrocracking.

http://en.wikipedia.org/wiki/Synthetic_oil
Uh huh...lol
__________________
/ 2002 WJ 4.7 H.O. / Flowmaster 50 SUV / Magnaflow Cats / Rocking that 2WD! /
Jer-Bear is offline   Reply With Quote Quick reply to this message
Unread 07-08-2013, 09:19 AM   #14
KayCeeJeep
Registered User
2004 WJ 
 
Join Date: Apr 2011
Location: Kansas City, Missouri
Posts: 1,118
Rotella is an excellent choice for the 4.0. Heavy duty and a thick 10w30, affordable, high in ZDDP and used oil analysis done when using Rotella in the 4.0 have shown very low wear numbers as well.
KayCeeJeep is offline   Reply With Quote Quick reply to this message
Unread 07-08-2013, 09:22 AM   #15
briandor
Registered User
2004 WJ 
 
Join Date: Feb 2013
Location: Sinking Spring, Pa
Posts: 196
Quote:
Originally Posted by Jer-Bear View Post
Uh huh...lol
Yea, I know. After I hit send I realized I wrote a book.
briandor is offline   Reply With Quote Quick reply to this message
Reply

Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the JeepForum.com forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.
User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid e-mail address for yourself.
Note: All free e-mails have been banned due to mis-use. (Yahoo, Gmail, Hotmail, etc.)
Don't have a non-free e-mail address? Click here for a solution: Manual Account Creation
Email Address:

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.


Thread Tools






Jeep, Wrangler, Cherokee, Grand Cherokee, and other models are copyrighted and trademarked to Jeep/Chrysler Corporation. JeepForum.com is not in any way associated with Jeep or the Chrysler Corp.