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Unread 12-08-2010, 11:38 AM   #1
royhkeith
Registered User
2010 KK Liberty 
 
Join Date: Nov 2010
Location: Silver Springs, FL
Posts: 58
3.7L performance

Motor home articles and other reviews I have read concerning the 3.7L Jeep Liberty engine note that it has poor performance. I found one report stating that it has twin overhead cams but only 2 valves/cylinder and that this design was chosen to obtain max torque at a lower RPM. It stated that this was a better choice for heavier load, off road use. 4 valves/cylinder and different valve timing evidentally would give better performance at higher RPM's, but the torque peak would also be at a much higher RPM.

Almost all my driving occures in the 1800-2000 RPM range, and @2500 RPM in tow mode while towing a pontoon boat at hwy speeds. I chose Jeep for towing the boat, off-roading on logging roads in the mts, and to be towed 4 wheels down behind a motorhome, plus use it as my only "family" vehicle, driven by my wife and myself. It will be driven @ 7500mi/yr and towed @ 25,000mi/yr. Almost all our long distance trips are via the motorhome. I've not yet felt I did not have all the power and acceleration I need for my use. I'd like more mpg, but realize this a heavy duty vehicle with 4WD. (I average 17-18mpg suburban driving)

My main concern is to have a long-life, reliable, engine and driveline. I feel the Jeep is not designed to be a high performance highway vehicle and is receiving a bad rap from some on this score.

What is the reliability record of this engine since it was introduced?

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Unread 12-08-2010, 11:49 AM   #2
SCT100
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2010 KK Liberty 
 
Join Date: Oct 2010
Location: Charleston, SC
Posts: 22
The 3.7 is in everything from Rams, to Dakotas, to the Liberty. As far as I know and from what I have seen, the motor is reliable (it's the tranny that can be so-so). It's a truck motor designed for torque as you stated (built for loads and strength), and considering how many there are, I think you would have heard if it was unreliable. As far as performance, it eats gas and doesn't make any power up high (as a variable cam motor would), but is otherwise a stout motor.

Ps. my company has had many, many Libertys over the years, and to my knowledge none of the motors has ever given us a problem...and these things get used off-road quite a bit. It's the transmissions that have to be repaired from time to time.

Last edited by SCT100; 12-08-2010 at 11:51 AM.. Reason: ps
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Unread 12-08-2010, 12:04 PM   #3
tjkj2002
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2002 KJ Liberty 
 
Join Date: Dec 2009
Location: Colorado
Posts: 7,948
Quote:
Originally Posted by royhkeith View Post
Motor home articles and other reviews I have read concerning the 3.7L Jeep Liberty engine note that it has poor performance. I found one report stating that it has twin overhead cams but only 2 valves/cylinder and that this design was chosen to obtain max torque at a lower RPM. It stated that this was a better choice for heavier load, off road use. 4 valves/cylinder and different valve timing evidentally would give better performance at higher RPM's, but the torque peak would also be at a much higher RPM.

Almost all my driving occures in the 1800-2000 RPM range, and @2500 RPM in tow mode while towing a pontoon boat at hwy speeds. I chose Jeep for towing the boat, off-roading on logging roads in the mts, and to be towed 4 wheels down behind a motorhome, plus use it as my only "family" vehicle, driven by my wife and myself. It will be driven @ 7500mi/yr and towed @ 25,000mi/yr. Almost all our long distance trips are via the motorhome. I've not yet felt I did not have all the power and acceleration I need for my use. I'd like more mpg, but realize this a heavy duty vehicle with 4WD. (I average 17-18mpg suburban driving)

My main concern is to have a long-life, reliable, engine and driveline. I feel the Jeep is not designed to be a high performance highway vehicle and is receiving a bad rap from some on this score.

What is the reliability record of this engine since it was introduced?
The 3.7 is a single overhead cam engine.It's pretty reliable and no timing belt to worry about ever,uses 3 timing chains.It's no race car engine but get's the job done,in a 4000lbs brick don't expect good mpg's and not what a Jeep is for anyways.Don't even compare it to a FWD with rear assist car-based platform croossovers like Escapes,Rav4's,and CRV's as they are not even close to a Liberty in anyway.

I have the same engine in my '02 Liberty and now my Liberty is weighing over 6000lbs and it does just fine(regeared of course),not going to win any races but not bad at all.MPG's,well we won't go there like I said it does weigh over 6k.The engine has never given me any issues,though I do change the oil every 3k with synthetic and change the plugs every year.
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'02 Liberty sitting on 35" tires,HP44,RockJock60,and AtlasII t-case
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Unread 12-08-2010, 05:52 PM   #4
armedsks
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2009 JK Wrangler 
 
Join Date: Jan 2009
Location: Sharpsburg
Posts: 87
Make sure to maintain per the owners manual or sooner. Id reccomend servicing the tranny every 30 or 60K miles.


Always seems like when the original tranny takes a crap, the remans never deliver OE quality,
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Unread 12-09-2010, 06:20 AM   #5
royhkeith
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2010 KK Liberty 
 
Join Date: Nov 2010
Location: Silver Springs, FL
Posts: 58
Thanks for the advice & info. So far very happy with my choice.
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