Need Source For Jeep Liberty Advice

[AZJeff]

My wife has a 2004 Liberty that we have owned since knew.  It has 121K miles on it, and it runs just fine, with no issues...no noises, no leaks, no oil consumption.

 

However, I know that the 3.7L engine in the vehicle has timing chains the drive the camshafts, and these are tensioned by oil pressure driven tensioners.

 

I am seeking some advice as to when it would be considered prudent to replace these chains and tensioners.  Since this is an "interference" engine, I don't want to wait until a chain jumps time and trashes the engine.

 

Can anyone point me to a reliable source as to how long this valve train can go before it should be replaced.  Thanks.

[howeitsdone]

Jeep Forum is pretty active. I'm over there for my WK2 and it's been great!

 

This is the general area
https://www.jeepforum.com/forums/jeep-liberty-forums.291/

 

And this is specific to the early models

https://www.jeepforum.com/forums/kj-liberty-forum.28/

[eaglescout526]

I can check the service library if you’d like. 

[Pete M]

I follow some FB KJ pages and can't say I've ever heard anyone ask that question or suggest changing them or say that they roasted the engine that way.    usually the 3.7 engine dies by overheating or dropping a valve or blowing a head gasket.

[cruiser54]

I know the 3.7 and 4.7 are fussy about the oil used and the intervals that the oil is changed.

 

I'm betting you are okay in that department. 

[dante2]

My wife had an 04 that she bought at 55k. Sold it back in 2020 when she got her JL. I did all of the maintenance/repairs on it and that was never done. When it sold it had over 250k and was still going strong. We would have kept it but 5 vehicles and 2 drivers is a bit much for us. 

[AZJeff]

3 hours ago, cruiser54 said:

I know the 3.7 and 4.7 are fussy about the oil used and the intervals that the oil is changed.

 

I'm betting you are okay in that department. 

Its been living on Mobile One, changed every 4-5K miles since new.  I changed the valve cover gaskets last year, and the top end was a clean as could be, so I guess the change intervals and oil choice is doing it's part.

[AZJeff]

19 hours ago, eaglescout526 said:

I can check the service library if you’d like. 

I figured you might have some intelligence on this.  That would be appreciated if you could check the library..

[AZJeff]

Just in case you are wondering why I am concerned about the camshaft drive system on the 3.7L engine:

 

My son has a Ford F150 with the infamous 5.4L Triton engine with the VVT.  These things are NOTORIOUS for having the "cam phasers" that control valve timing dying and causing catastrophic valve train damage.  In addition, the chain drive wears inordinately, and can cause chain jump because the tensioners cannot accommodate gross chain stretch.

 

Owing to this, we decided to be proactive on his truck at just below the 200K mark.  (Many of these  engine croak LONG before this due to this valve train problem.)  Because my son had been VERY diligent about oil changes and using synthetic oils, the valve train was still functioning, but there was no doubt that the chains were getting sloppy, and it was inevitable that the system would die in a catastrophic way in the not-too-distant future.  We dodged  a bullet by doing the cam drive system proactively.  Parts were not cheap, but they were cheaper than a new/used engine.

 

I just want to make sure the 3.7L Jeep engine doesn't have a similar latent defect in the cam drive system as does the Triton, and this is why I asked the question.

[eaglescout526]

1 hour ago, AZJeff said:

I figured you might have some intelligence on this.  That would be appreciated if you could check the library..

I am not seeing anything in terms of maintenance to the timing.  I did find this:

 

MEASURING TIMING CHAIN WEAR

 

 

1 - SECONDARY TENSIONER ARM

2 - SECONDARY CHAIN TENSIONER PISTON

 

NOTE: This procedure must be performed with the timing chain cover removed.

1. Remove the timing chain cover (Refer to 9 - ENGINE/VALVE TIMING/TIMING BELT/CHAIN AND SPROCKETS - REMOVAL).
2. To determine if the secondary timing chains are worn, rotate the engine clockwise until maximum tensioner piston (2) extension is obtained. Measure the distance between the secondary timing chain tensioner housing (Measuring Secondary Timing Chains For Wear) and the step ledge on the piston. The measurement at point (A) must be less than 15mm (.5906 inches).
3. If the measurement exceeds the specification the secondary timing chains are worn and require replacement (Refer to 9 - ENGINE/VALVE TIMING/TIMING BELT/CHAIN AND SPROCKETS - REMOVAL).

 

DO NOT CLICK THE LINKS, THEY WILL TAKE YOU TO THE SERVICE LIBRARY IN WHICH NO ONE WITHOUT DEALER CLEARANCE CAN ACCESS.

[jdog]

I get 404 error when I click on the links lol.

[eaglescout526]

46 minutes ago, jdog said:

I get 404 error when I click on the links lol.

Lol what did I say. Well glad it’s a 404 and not a log in screen

[jdog]

Me too

[AZJeff]

I actually have the Liberty shop manual, and to measure chain wear as described above, you have to remove the Timing chain cover and all the crap in front of it.🙁

 

once I am that far in on a 120k engine, I AM putting new parts in.

[dasbulliwagen]

As a former Jeep dealership tech, I can say we never had any issues with the 3.7/4.7 timing components. This is especially true if you do the required regular maintinance. Those engines are very intolerant of poor maintinance which has given them a bad name. 

[mjeff87]

Trust me, BTDT.  If you're past the point of the timing cover (more like "entire front end of the engine cover"), you're putting new crap in it.

 

Getting all three timing chains lined up correctly can be a PITA but doable.  There's a little plastic wedge tool you can buy to hold the right side chain in place but I fashioned one up out a little wedge of wood and some rope.  You actually have to rotate the right side cam about 20 degrees clockwise ( against valve spring pressure) to get the timing gear to line up correctly, before bolting the gear down.

 

ETA:  agree 100% with dasbulliwagen.  Treat the cooling system and oiling system with utmost care.

 

 

[AZJeff]

Thanks, guys.   Since I know this engine has been well cared for it’s entire life (along with PM to the cooling system like new rad, new WP, new hoses (twice for those) plus 4 coolant changes in 120k miles, I think I am safe with the engine as is.

 

Here in PHX, a cooling system that is not absolutely PERFECT will kill an MJ/XJ real quick in the summer.   I have carried over that practice into the wife’s KJ, and it seems to be paying off.

[mjeff87]

In my very short list of complaints about my KJ (I really do like it, but some things bug me) at the very top is my obsession with the cooling system.  I'm almost paranoid about it, because I know exactly what a failure will cause.  I'm constantly keeping an eye on the temp gauge every time I drive it, and honestly, for any sort of modern-ish vehicle noone should have to do that.  Some don't give a crap about it, and they're the ones with blown headgaskets/warped heads/junked 3.7's though.  Sucks to be them.

[dante2]

3 hours ago, mjeff87 said:

In my very short list of complaints about my KJ (I really do like it, but some things bug me) at the very top is my obsession with the cooling system.  I'm almost paranoid about it, because I know exactly what a failure will cause.  I'm constantly keeping an eye on the temp gauge every time I drive it, and honestly, for any sort of modern-ish vehicle noone should have to do that.  Some don't give a crap about it, and they're the ones with blown headgaskets/warped heads/junked 3.7's though.  Sucks to be them.

We had an 03 and 04 that were past 250k when we sold them. I was pretty watchful of the temp gauge as well. Both were inexpensive to own and didn't owe us anything.

[mjeff87]

My 02 only has 145K on it...I don't drive it much anymore.  It will be around for quite awhile, lol.

 

That pic I posted was from a couple years ago, when I accidentally snapped off the #6 plug in the head.  I ended up having to pull the head to get the remnants removed and the hole retapped at a machine shop, then put it all back together.  I knew it was going to be off the road for awhile while I worked on it, so I picked up a cheap little Ford Focus to get around in while it was deadlined, with the intention of reselling it (the Focus) once I got the KJ fixed.  Well, that never happened....I ended up keeping and driving the Focus as a DD once I got the KJ back on the road.  It's a 5-speed, and gets about 32-34 mpg in mixed driving and costs me about nothing to drive.  Quite unlike the KJ.

 

I still try to drive it at least once a week, and use it to pull my trailer when needed.  If and when it ever snows down here it also pulls inclement weather duty.