2008 Jeep Liberty Engine Failure - JeepForum.com

 
LinkBack Thread Tools
post #1 of 12 Old 02-05-2011, 07:12 PM Thread Starter
SuperRliBerty
Registered User
2008 KK Liberty 
 
Join Date: Jan 2010
Location: Florida
Posts: 1,442
2008 Jeep Liberty Engine Failure

Found this in an austrailian Jeep forum. I showed it to my mechanic friend and he said either oil starvation, over-revving or camshaft mod failure can cause that:

2008 Jeep Liberty w/63,000 miles. Broke cylinder #4 intake valve spring, which caused the rocker arm to become jammed between the lifter and the cam. Result..... Note this is the 3rd late model Chrysler product this year breaking valve train components and ruining heads. The other 2 were Hemi's.

Attached Thumbnails
0617001602.jpg  

2008 Sport Liberty
Cold air intake*Trush (magnaflow) turbo muffler* Hypertech power program*
Hood Prop mod. Battery Quick Release mod.
Resonator removed (sounds like a V8 on start up)
SuperRliBerty is offline  
Sponsored Links
Advertisement
 
post #2 of 12 Old 02-05-2011, 07:28 PM
tjkj2002
Registered User
2002 KJ Liberty 
 
Join Date: Dec 2009
Location: Colorado
Posts: 8,393
Well you can't over-rev the engine,the PCM will not allow it.76,000 miles on mine and it bounces of the rev limiter at least 10 times a day so that is a non-issue.

'02 Liberty sitting on 35" tires,HP44,RockJock60,and AtlasII t-case
tjkj2002 is offline  
post #3 of 12 Old 02-05-2011, 07:37 PM Thread Starter
SuperRliBerty
Registered User
2008 KK Liberty 
 
Join Date: Jan 2010
Location: Florida
Posts: 1,442
Quote:
Originally Posted by tjkj2002 View Post
Well you can't over-rev the engine,the PCM will not allow it.76,000 miles on mine and it bounces of the rev limiter at least 10 times a day so that is a non-issue.
do you do redline shift ten times a day? Do it for another 76,000 miles.

Have you done a compression test on that engine?

2008 Sport Liberty
Cold air intake*Trush (magnaflow) turbo muffler* Hypertech power program*
Hood Prop mod. Battery Quick Release mod.
Resonator removed (sounds like a V8 on start up)
SuperRliBerty is offline  
post #4 of 12 Old 02-05-2011, 08:02 PM
richd
Registered User
2008 KK Liberty 
 
Join Date: Jun 2008
Location: Arizona
Posts: 1,110
I know there are issues with the HEMIs with valve spring breakage,and bad valve guides,so it looks like Chrysler is have some engineering problems.
richd is offline  
post #5 of 12 Old 02-05-2011, 08:06 PM
DaveJKJ
Registered User
2005 KJ Liberty 
 
Join Date: Nov 2008
Location: Upstate NY
Posts: 1,103
Quote:
Originally Posted by tjkj2002 View Post
Well you can't over-rev the engine,the PCM will not allow it.76,000 miles on mine and it bounces of the rev limiter at least 10 times a day so that is a non-issue.
How many rpms is the 3.7L rev limiter set at?

Lifted, Skids, Hooks, Rails, Trail Rash..
War Veterans Jeep Group #31
Black Jeep Society #217
DaveJKJ is offline  
post #6 of 12 Old 02-05-2011, 08:56 PM Thread Starter
SuperRliBerty
Registered User
2008 KK Liberty 
 
Join Date: Jan 2010
Location: Florida
Posts: 1,442
Quote:
Originally Posted by DaveJKJ View Post
How many rpms is the 3.7L rev limiter set at?
6000 rpm

2008 Sport Liberty
Cold air intake*Trush (magnaflow) turbo muffler* Hypertech power program*
Hood Prop mod. Battery Quick Release mod.
Resonator removed (sounds like a V8 on start up)
SuperRliBerty is offline  
post #7 of 12 Old 02-05-2011, 08:58 PM Thread Starter
SuperRliBerty
Registered User
2008 KK Liberty 
 
Join Date: Jan 2010
Location: Florida
Posts: 1,442
Quote:
Originally Posted by richd View Post
I no there are issues with the HEMIs with valve spring breakage,and bad valve guides,so it looks like Chrysler is have some engineering problems.
probably in the cast process of the cylinder head.

2008 Sport Liberty
Cold air intake*Trush (magnaflow) turbo muffler* Hypertech power program*
Hood Prop mod. Battery Quick Release mod.
Resonator removed (sounds like a V8 on start up)
SuperRliBerty is offline  
post #8 of 12 Old 02-05-2011, 10:11 PM
tjkj2002
Registered User
2002 KJ Liberty 
 
Join Date: Dec 2009
Location: Colorado
Posts: 8,393
Quote:
Originally Posted by SuperRliBerty View Post
do you do redline shift ten times a day? Do it for another 76,000 miles.

Have you done a compression test on that engine?
The rev limiter is there for a reason,it cuts of fuel to prevent damage.The redline(rev limiter) is alot lower then the actual rpm's needed to do damage in which case is called "floating the valves",basically when the valve spring can not open/close the valve quick enough.The 3.7 was operated at "redline" for several hundred hours with no damage on a dyno,along with every other engine produced today.If hitting the redline would cause damage they would set the redline(rev limiter) much lower then what it is already set at.A little common sense goes along way.


Oh and yes I have done a compression test and well above min specs,just remember the 3.7 does not make peak HP till 400 rpm shy of redline.

'02 Liberty sitting on 35" tires,HP44,RockJock60,and AtlasII t-case
tjkj2002 is offline  
post #9 of 12 Old 02-06-2011, 04:33 PM Thread Starter
SuperRliBerty
Registered User
2008 KK Liberty 
 
Join Date: Jan 2010
Location: Florida
Posts: 1,442
Quote:
Originally Posted by tjkj2002 View Post
If hitting the redline would cause damage they would set the redline(rev limiter) much lower then what it is already set at.A little common sense goes along way.
Absolutely! common sense goes a long way. But hitting the rev limiter 10 times a day will not. If you speak with the designer and builder of the 3.7L I am positively sure they will agree with Hitting the rev limiter 10 times a day for 76,000 miles, but hey, to each his own.

I hit the speed limiter once before in my libby on I-75, 110 mph@ 5500rpm before the computer starts cutting fuel and retarding the timing.

2008 Sport Liberty
Cold air intake*Trush (magnaflow) turbo muffler* Hypertech power program*
Hood Prop mod. Battery Quick Release mod.
Resonator removed (sounds like a V8 on start up)
SuperRliBerty is offline  
post #10 of 12 Old 02-06-2011, 06:54 PM
tjkj2002
Registered User
2002 KJ Liberty 
 
Join Date: Dec 2009
Location: Colorado
Posts: 8,393
Quote:
Originally Posted by SuperRliBerty View Post
Absolutely! common sense goes a long way. But hitting the rev limiter 10 times a day will not. If you speak with the designer and builder of the 3.7L I am positively sure they will agree with Hitting the rev limiter 10 times a day for 76,000 miles, but hey, to each his own.

I hit the speed limiter once before in my libby on I-75, 110 mph@ 5500rpm before the computer starts cutting fuel and retarding the timing.
Yeah like to see how many times your 3.7 would hit the rev limiter when trying to move 2000lbs more weight in Colorado.Hitting the rev limiter will not damage the engine as long as you have oil pressure,if it does you have/had a underlying problem that was the reason for the failure and not hitting the rev limiter.

My '84 Blazer I used for mud drag racing was bouncing off the 7500rpm limiter(MSD 6AL box limited) most of it's life with a 355,never hurt a thing.Would also go up to 7000rpm in my Cutlas with a 350 Rocket(big block),about 500rpm short of "floating the valves"(no rev limiter) and never had a issue either.Pulled alot of long distance/high speed trips in that car with it over 6000 rpm's as it only had a 3 speed trans,and talking about 75+ miles runs here on back roads.

'02 Liberty sitting on 35" tires,HP44,RockJock60,and AtlasII t-case
tjkj2002 is offline  
post #11 of 12 Old 02-06-2011, 10:34 PM
VMF
Registered User
2008 KK Liberty 
 
Join Date: Jan 2009
Location: New York
Posts: 579
i race my civic in auto X and onon the 1/4 mile. rpms go all the way to 9500 and it has 5300 miles and still going strong. reaching the rev limiter is indeed not that bad. go over it and you see the valves flying through the hood. been there, done that

___________________________
2008 KK limited 4x4. Inferno Red
2009 JK Rubicon. Black
2004 UCF31. Black
2001 EM2. Inca pearl
2012 UD Limited. Royal Gray
VMF is offline  
post #12 of 12 Old 02-07-2011, 07:44 AM Thread Starter
SuperRliBerty
Registered User
2008 KK Liberty 
 
Join Date: Jan 2010
Location: Florida
Posts: 1,442
Quote:
Originally Posted by tjkj2002 View Post
Yeah like to see how many times your 3.7 would hit the rev limiter when trying to move 2000lbs more weight in Colorado
Unfortunately you will not be able to see that. My driving habits does not allow me to hit the rev limiter.

2008 Sport Liberty
Cold air intake*Trush (magnaflow) turbo muffler* Hypertech power program*
Hood Prop mod. Battery Quick Release mod.
Resonator removed (sounds like a V8 on start up)
SuperRliBerty is offline  
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.



Email Address:
OR

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.




Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page



Similar Threads
Thread Thread Starter Jeep Forums Replies Last Post
2008 Jeep Liberty ESP/TCS Indicator lights stuck on tajee KK Liberty Forum 12 01-06-2013 11:10 PM
which lift for 2008 liberty kk flaglfr KK Liberty Forum 0 02-01-2011 09:53 PM
2008 Jeep Liberty cd shop manual SuperRliBerty KK Liberty Forum 0 12-21-2010 05:33 PM
Jeep Liberty Recall (KK) 2008 to present SuperRliBerty KK Liberty Forum 4 12-12-2010 02:49 PM
Jeep Liberty Engine Break IN casadelrob KK Liberty Forum 2 08-12-2010 05:50 AM

Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome