Motor oil for the 3.8. - 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 Wrangler Forums > JK Wrangler Technical Forum > Motor oil for the 3.8.

XHD Heavy-Duty Hood Latches for JK and TJ available at OcoStainless Steel Door Hinge PinsPoly Door Hinge Bushings

Reply
Unread 08-03-2011, 06:21 PM   #1
BacasJK
Registered User
2011 JK Wrangler 
 
Join Date: Aug 2011
Location: Arlington, TX
Posts: 178
Motor oil for the 3.8.

Hello everyone,
I'm new to the forum, just bought a 2011 Rubicon 3 weeks ago and just love it. Big change from my Dakota R/T but after eleven years with the truck, it was time for some real fun and to grow up. lol
Anyway, It probably has been mention before but I'm getting ready to change the oil at 1000 miles and was wondering what other 3.8 owners recommend.
I'm a super big fan of Mobil 1 and used it in all my vehicles. Some engines are different and this V6 is first for me ever. I'm not to crazy about the recommended weight 5-20w oil and will probably use a 5-30w oil. I might even try the 0-40w that i used to use in my V8s. Damn good oil!
Shoot me some ideas what you guys recommend. I believe some engines run better on different brands.
Thanks

Martin- new owner of 2011 Rubicon

BacasJK is offline   Reply With Quote
Unread 08-03-2011, 07:08 PM   #2
Shenck
Registered User
2007 JK Wrangler 
 
Join Date: Jun 2004
Location: Rochester, N.Y.
Posts: 164
Welcome to the JK/Rubicon family. I also am not a fan of the 5-20W oil. I use 5-30W in all my jeeps and never had an issue. As far as what brand of oil - I'm not going to open that pandoras box so choose what brand you like and enjoy.
__________________
------ED-----
2007 Rubicon 6-Speed, 3" Lift with 35's
1993 Cherokee Country, 3" AAL. with soft 8's & 31's
Shenck is offline   Reply With Quote
Unread 08-03-2011, 08:08 PM   #3
tchaap
Registered User
2008 JK Wrangler 
 
Join Date: Jul 2010
Location: Kennesaw, Georgia
Posts: 400
mobil 1 5/20 works great for me.
__________________
TC
tchaap is offline   Reply With Quote
Unread 08-04-2011, 04:20 AM   #4
run11rb
Registered User
2011 JK Wrangler 
 
Join Date: Nov 2010
Location: Norfolk, Virgina
Posts: 192
I use AMSOIL 0W20. Thats what they recommended but i hear everyone use everyother kind of oil so at this point its all about where your faith(in oils) lye.
__________________
2011 JK Rubicon, Volant CAI, Viper TB, grab handles, floor mats and the Smittybuilt overhead console
run11rb is offline   Reply With Quote
Unread 08-04-2011, 05:54 AM   #5
WXman
Registered User
2001 WJ 
 
Join Date: Jun 2003
Location: Kentucky
Posts: 3,010
My 2011 owners manual specifically states that 5W20 ONLY is recommended. Then it goes on to state specifically that using anything other than what's recommended may void your warranty.

If you want, I can post the specific wording used in the warranty guide. Bottom line is.. I hate using 5W20 too, but until the warranty is gone on this thing, that's what it's going to get.


3.3 Maintenance Costs Not Covered
Your warranties don’t cover the costs of repairing
damage caused by poor or improper maintenance. Nor
do they cover damage caused by the use of contaminated
fuels, or by the use of fuels, oils, lubricants,
cleaners or fluids other than those recommended in
your Owner’s Manual.

3.6 Other Exclusions
Your warranties don’t cover the costs of repairing
damage or conditions caused by any of the following:
......
......
• using any fluid that doesn't meet the minimum
recommendations in your Owner's Manual.
__________________
'92 YJ - heavily modded
'96 ZJ - heavily modded
'05 KJ CRD Limited - 370 lb./ft. from a 4-cylinder and trail ready. Pure awesomeness.
'11 Mango Tango JKU Sport - Mods
'12 Dozer JKU Sport S - 6-speed - ACE rock rails - Max Tow package - Daystar spacers - 33x12.50 Duratracs
WXman is online now   Reply With Quote
Unread 08-04-2011, 06:48 AM   #6
Joevacs
Registered User
2010 JK Wrangler 
 
Join Date: Sep 2010
Location: Hickory, NC
Posts: 1,236
WELCOME

I use Mobil 1, 5W20..........

why do yall not like 5W20 ? What's wrong with it? please splain
__________________
2010 Rubicon, 4" lift, Currie control arms and trackbar, 37x12.5x17 Goodyear MT/R kevlar
Joevacs is offline   Reply With Quote
Unread 08-04-2011, 06:59 AM   #7
PhatJK
Registered User
2009 JK Wrangler 
 
Join Date: Apr 2009
Location: California
Posts: 303
Welcome to the forum. I use Mobil 1 5W20. Unless there is something wrong with the engine, I would use the Jeep recommendation. They designed their engine with 5W20 oil specs and ran all durability testing with it. I am not sure why people have one preference of oil weight versus another since they all cost the same for the same brand of oil.
__________________
[URL="http://www.flickr.com/photos/14945982@N08/"]My Flickr Page[/URL]

[SIZE="3"][COLOR="White"][B]09 Unlimited Rubicon [/B][/COLOR][/SIZE]

Teraflex 2.5" spring lift kit
ORFAB tire carrier
PhatJK is offline   Reply With Quote
Unread 08-04-2011, 07:06 AM   #8
Joevacs
Registered User
2010 JK Wrangler 
 
Join Date: Sep 2010
Location: Hickory, NC
Posts: 1,236
Quote:
Originally Posted by PhatJK View Post
Welcome to the forum. I use Mobil 1 5W20. Unless there is something wrong with the engine, I would use the Jeep recommendation. They designed their engine with 5W20 oil specs and ran all durability testing with it. I am not sure why people have one preference of oil weight versus another since they all cost the same for the same brand of oil.
that's what I was thinking... i would sure like to hear the reasoning behind choosing a different weight.
__________________
2010 Rubicon, 4" lift, Currie control arms and trackbar, 37x12.5x17 Goodyear MT/R kevlar
Joevacs is offline   Reply With Quote
Unread 08-04-2011, 07:07 AM   #9
Millermagic
Registered User
2000 XJ Cherokee 
 
Join Date: Apr 2007
Location: Syracuse, New York
Posts: 1,889
With the reputation the 3.8 has for spinning bearings, you're going to want to keep the warranty in tact.

I'd feel more comfortable running the lightest oil recommended for the engine than something heavier. Flow, not pressure, lubricates the engine.

a 0-20 would be nice for winter.
__________________
2000 XJ - 3.5'' Lift & Skinny Mudders.
Previous: A CJ, Few TJs and JK.
Millermagic is offline   Reply With Quote
Unread 08-04-2011, 07:34 AM   #10
jstrubberg
Registered User
2009 JK Wrangler 
 
Join Date: Jul 2010
Location: Missouri
Posts: 2,124
The 3.8 doesn't have a reputation for spinning bearings. One lot of motors back in 2008 that were made in a mexican plant had this problem. It was corrected long ago.

I would only use 5-20 myself. Used to be, engines needed the additional viscosity to prevent thermal breakdown. Now, the issue is the oil needs to be thinner to make it past the tighter tolerances inside the engine.
jstrubberg is offline   Reply With Quote
Unread 08-04-2011, 07:56 AM   #11
dsjk
Registered User
2011 JK Wrangler 
 
Join Date: Feb 2011
Location: jacksonville, Florida
Posts: 605
Well my 2007 JKU was one of the ones that spun a bearing at 74,000 miles even after running Mobil 1 5w-20 and changing regularly. Jeep blamed me and the dealership wouldn't do anything so I found a guy that was wanting to do a motor swap and sold it to him and got an incredible deal on a 2011 due to my experience.

Since then I now run Mobil 1 10w-30 synthetic....


Why you ask, though I understand the arguement that it "Flow, not pressure, lubricates the engine" after speaking with a few mechanics and engineers I have learnt that the 5w is thin and often does not reduce friction as much as you would find in a heavier weight and the 20 thins out even more as the temp. goes up reducing the lubrication even more. I live in FL so the heat is always pretty high as it is so with high heat the 10w-30 I run more often acts like a 5w-20.

If I lived in a cooler area I would stick with the 5w-20 but having already blown one engine I am trying to protect myself from doing it again.

I have even spoke with Jeep about my choice and was told that in their testing the 5w-20 gave the balance of engine wear and MPG that met federal requirements but was also told that thought the 10w-30 would provide more protection it would also result in a loss of MPG....I drive a Jeep who cares about MPG lol

Now I could be completely wrong about things as I am not a mech. engineer but as stated I did consult GA Tech and one MIT mech engineer none of which have as much knowledge as oil specialist ind. engineer. I do however, trust their knowledge base.
__________________
[CENTER][URL="http://www.rockkrawler.com/?r_intro=1"][FONT="Arial Black"][B][COLOR="Black"]ROCK KRAWLER[/COLOR][/B][/FONT][/URL] [URL="http://www.4x4spod.com/"][FONT="Showcard Gothic"][COLOR="SeaGreen"]S-POD[/COLOR][/FONT][/URL] [URL="http://www.milemarker.com/"][FONT="Impact"][COLOR="DarkOrange"]MILE MARKER[/COLOR][/FONT][/URL]
[URL="http://www.aceengineeringandfab.com/"][FONT="Fixedsys"][B][SIZE="5"][COLOR="Red"]A.C.E.[/COLOR][/SIZE][/B][/FONT][/URL][/CENTER]

[QUOTE=voodooJK;11973781]Something you said after the fact exposed that part of me... like a catholic school girl normally would.[/QUOTE]
dsjk is offline   Reply With Quote
Unread 08-04-2011, 08:50 AM   #12
mtljeep
Registered User
2000 WJ 
 
Join Date: Nov 2009
Location: Montreal,Canada
Posts: 97
Quote:
Originally Posted by dsjk View Post
Well my 2007 JKU was one of the ones that spun a bearing at 74,000 miles even after running Mobil 1 5w-20 and changing regularly. Jeep blamed me and the dealership wouldn't do anything so I found a guy that was wanting to do a motor swap and sold it to him and got an incredible deal on a 2011 due to my experience.

Since then I now run Mobil 1 10w-30 synthetic....


Why you ask, though I understand the arguement that it "Flow, not pressure, lubricates the engine" after speaking with a few mechanics and engineers I have learnt that the 5w is thin and often does not reduce friction as much as you would find in a heavier weight and the 20 thins out even more as the temp. goes up reducing the lubrication even more. I live in FL so the heat is always pretty high as it is so with high heat the 10w-30 I run more often acts like a 5w-20.

If I lived in a cooler area I would stick with the 5w-20 but having already blown one engine I am trying to protect myself from doing it again.

I have even spoke with Jeep about my choice and was told that in their testing the 5w-20 gave the balance of engine wear and MPG that met federal requirements but was also told that thought the 10w-30 would provide more protection it would also result in a loss of MPG....I drive a Jeep who cares about MPG lol

Now I could be completely wrong about things as I am not a mech. engineer but as stated I did consult GA Tech and one MIT mech engineer none of which have as much knowledge as oil specialist ind. engineer. I do however, trust their knowledge base.
WOAHHHH..........so let me get this straight.......u were using the recomended oil, and they sill didn't honor the warranty?
mtljeep is offline   Reply With Quote
Unread 08-04-2011, 09:07 AM   #13
dsjk
Registered User
2011 JK Wrangler 
 
Join Date: Feb 2011
Location: jacksonville, Florida
Posts: 605
Quote:
Originally Posted by mtljeep View Post
WOAHHHH..........so let me get this straight.......u were using the recomended oil, and they sill didn't honor the warranty?
Yes they did, even after to Jeep engineers looked at, one service tech, service manager, and a few conference calls with Jeep Headquarters where I supplied proof that I was not the only one having this problem and that I followed the proper maintnance. Crazy thing is that the bearing spun right after having my oil changed at the dealership.

They told me if I had about 10000 or 12000 miles less they prob would have covered but not at aprox. 74,000 miles.

Then I was trying to work a deal with the dealership to get a new jeep and they pulled a bait and switch offer on me.
__________________
[CENTER][URL="http://www.rockkrawler.com/?r_intro=1"][FONT="Arial Black"][B][COLOR="Black"]ROCK KRAWLER[/COLOR][/B][/FONT][/URL] [URL="http://www.4x4spod.com/"][FONT="Showcard Gothic"][COLOR="SeaGreen"]S-POD[/COLOR][/FONT][/URL] [URL="http://www.milemarker.com/"][FONT="Impact"][COLOR="DarkOrange"]MILE MARKER[/COLOR][/FONT][/URL]
[URL="http://www.aceengineeringandfab.com/"][FONT="Fixedsys"][B][SIZE="5"][COLOR="Red"]A.C.E.[/COLOR][/SIZE][/B][/FONT][/URL][/CENTER]

[QUOTE=voodooJK;11973781]Something you said after the fact exposed that part of me... like a catholic school girl normally would.[/QUOTE]
dsjk is offline   Reply With Quote
Unread 08-04-2011, 09:12 AM   #14
mtljeep
Registered User
2000 WJ 
 
Join Date: Nov 2009
Location: Montreal,Canada
Posts: 97
Ur the 2nd person I've heard of that chrysler has screwed.......I better not regret having bought this jeep
mtljeep is offline   Reply With Quote
Unread 08-04-2011, 09:19 AM   #15
jwmbishop
Registered User
2011 JK Wrangler 
 
Join Date: May 2011
Location: corsicana, tx
Posts: 3,126
It's not just a matter of lubing the bearing. Heck WATER would do that task with a larger clearance, a controlled temp and higher pressure (but would induce electrolysis and corrosion). The oil does not just lube - that no doubt is it's primary function BUT - it also cools, cleans, protects from corrosion and controls the valves via the hyd lifters.

Lets ignore the zero and look at the 20 or 30 weight. This is typical viscosity at 240 degrees. The 20 weight being thinner would flow more - removing more heat and cleaning more. If it REMOVES more heat that means it HOLDS more heat so would run at the temp range as designed. The 30 weight would flow less so remove and hold less heat. This means your bearings are now running hotter. Not a problem

Now take the oil temp down to 200. The 20 wt is now like the 30 was at 240. The 30 however is now too thick and can "gum" with contaminants and as it's thicker it won't splash into as much surface area and thus allow sludge to start forming.

This is considered in design and adjustments to tolerances are made. When you order a Jeep can you order it to have more or less bearing clearance or galley size or other orfice sizes?

Let's just look at the lifters for a second. The size of the hole that feeds the hyd pressure is set to the pump pressure at a given weight of oil. Increasing the weight means less volume to the lifters so they don't pump up as much - so you have taken ramp speed away at the lower RPM ranges when you increase the viscosity and compare at same temps. This is power loss - would still make max at max rpm - but you have removed some down where we really drive. Unless you always drive at 4800 rpm at all times.

There are MANY aspects of the designs being considered in oil choice. some aspects are engineered to the oil - in some the oil is engineered to the aspect. They go hand in hand.

But for me I will follow the recommends - I know the engineers do not sit up there and cackle like witches and plot a mean and devious course when they make their recommendations. They want to go home with the feeling of a job well done just like me. believing they have some sinister plan that deprives me of something or in some way challenges my masculinity or intelligence is called paranoia and if I ever get to that state I will look into prozac.

And yes I hear the argument: Well I have ALWAYS ran nothing lower than 40 weight and it has worked fine. Yea Grandpa - you used to drive a Model T with flat head four and poured bearings twenty miles to school in the snow uphill both ways! But seriously what did that show on the dyno at 2000 RPM? based on chemical analysis what was the difference in ability to trap, hold and remove with change any contaminants (corrosion protection)? What was the temp of the bearings at the surface? What was high temp and low temp in the engine? What was the difference in cling and wash in those hard to get places like the corners of the valve covers? NO ONE but the engineers can answer that unless they have a couple mil in equipment to test - and quantify their results.
__________________
J Wm Bishop EA, ASADE
How to start an online argument - express opinion - wait.
jwmbishop is offline   Reply With Quote
Reply
Thread Tools


Suggested Threads





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.