4.0 Cherokee Woes....

[nylyon-(Admin) 7,130]

Last winter my Cherokee (XJ) developed a nasty knock.  Well being the procrastinator that I am, I didn't get to looking into it until now.  I just finished dropping the oil pan (removing it will be another trick) and lo and behold, I found piston parts in the bottom of the oil pan.  I stopped for the day while I prepare my shopping list. 

 

The Jeep has 120K mikes on it, and is a little beat up but NO rust which is really nice.  It also has the transfer case which off-roaders HATE but for regular use, it's best and that's the select trac which is a 2wd, 4-lo and 4part time and 4 full time!  

 

So time to start my shopping list, and think of my plan of attack.  If anyone has done this and have any tips, I'm open to it.  What I can say, I plan to replace the broken parts only.  The engine is staying IN the Jeep, I may replace the rod bearings depending on how it looks when I remove the broken piston.

[Sparky-(Admin) 19,691]

_{I cant offer any advice on the repair but I thought those straight 6 motors were suppose to go 200k easy? What caused that to happened to yours?}

_{Mike.........}

[nylyon-(Admin) 7,130]

From what I read, there's a batch of bad pistons which made it into a lot of 4.0's.  Mine is a 2001 which seems to be affected.  The noise it makes is similar to a flat lifter.  This Jeep will be used by the kids mostly, so I'm sure that the engine will be the least of the issues when they're done with it.

 

Along with the piston, I need to replace the fan clutch and pre-cat's (this thing has California emissions and 3 catalytic converters with 4 O2 sensors) so it's going to cost a little bit to get this back going again, but still less than buying another car!

[19richie66 17,004]

Mine had about 156k on it when I put another motor out of a wrecked 98. That motor had 77k on it then and I drove that one till i sold it.. Tranny,transfer case and front axle had almost 300k on it when I sold it. They are great motors. Original motor in mine was overheated before I got it. It used a little oil but kept on going. Good luck Karl.

[nylyon-(Admin) 7,130]

I thought about putting in a long block, but since this will be the kids car, I doubt it'll make it very long so I'm going to fix what's wrong and put it back together.  We've had this Jeep for about 7 years, and aside from some initial repairs, it's been a great vehicle and it's a good size for parking!

[squonk 39,146]

I replaced a crank once in one of those 4.0's once but it was on the lift. Heavy rascal! 

[nylyon-(Admin) 7,130]

I stopped for the day, still have to get the oil pan out of there need to raise the Jeep a little more raise the jack stands, so it'll clear the front axle.

[JimD 3,345]

Karl, please be careful under there and use any and all safety precautions. There can't be enough overkill when it comes to your safety.

[nylyon-(Admin) 7,130]

Thanks pal   !  

 

It's sitting on jack stands (front only) with the front wheels still on, parking brake on, rear wheels chocked, in park in a level garage! It's sitting on the stands only to get the oil pan off, then it comes down again since I can work under the Jeep without it being hoisted up. 

[chazm 412]

Sorry to hear about your Jeep Karl, My 94 has 250k on the motor ,always had a knock when I got it in 95,my problem is the transfer case is shot,only running in 2wd now. If your changing the oil filter  mount o-ring good luck, what a PITA

[RMCIII 838]

Since you already got your shopping list bought, my input is a little late, but my suggestion was going to be go to a junk yard and buy a used motor for $400.00. By the time you do the swap you will be time saved = money saved. But since you are already into it, wish you well. I have a ZJ - 5.9. I have heard the horor stories about the "bad" pistons. Some guys had a couple go at once... Hope that does not happen to you once you get it back together. As for your NP231 transfer case, I'll swap yah! Mine has just 3 settings, AWD, 4-hi, 4-lo. Can't really complain about the gas mileage though..... Still is getting 17.8 on the highway running 70mph....Good luck.

 

Rob

[Ken B 3,116]

Ever put a junk yard engine or transmission in only to have it be just that, JUNK. Been there done that..

[19richie66 17,004]

My daughters 2000 Cherokee had 205k on it when we bought it for her 16th birthday. Two years later all we have done is the headliner, water pump and she had to have a stereo. Got it out back now tracing down a misfire. Narrowed it down to #4 cylinder. All things are pointing to a bad injector. Gonna swap two injectors and see if the miss follows. Hope that's all it is. Gotta do a valve cover gasket also. Not bad for 220k. Be safe Karl Rollin around under there.

[RMCIII 838]

Ever put a junk yard engine or transmission in only to have it be just that, JUNK. Been there done that..

 

 

 Must be the yeard where you got it from... Helped out several times putting them in, no issues, and a 60 day warranty to boot. If it is truly junk, you can find out, in those 60 days.

[nylyon-(Admin) 7,130]

I have a buddy who had a grand Cherokee.  His got the 4.0 tick (broken piston) and he replaced it with a junk yard engine only to last a year.  There's a couple of issues with the 2001's, so I think that I'll take my chances with the repair, so I don't have to replace then repair again!

[Ken B 3,116]

 Must be the yeard where you got it from... Helped out several times putting them in, no issues, and a 60 day warranty to boot. If it is truly junk, you can find out, in those 60 days.

I worked for a small garage for a few yrs. The owner there had a big heart and he would often try to help out customers with little money when their cars died. The fact is it has nothing to do with the yard you got the engine and or tranny from, it all boils down to how the previous owner took care of it and that is s toss up. Tons of people out there never change their oil. I had a few trannies and one engine take a dump within the 60 day warranty. The vehicle the engine crapped out in was in a van and it was no easy install. The yards stood tall and honored their warranty BUT they don't pay for the R&R of the crapped out unit... Even though the owner of the shop had to pay me again to R&R the engine in the van who wants to do that job twice in a month... I'm not saying purchasing from a salvage yard is a bad idea I'm just saying that sometimes it comes back to bite ya...