XJ Owner

[ktmrider]

New KJ owner

I'm a long time XJ owner that has acquired a high mileage KJ. It's a 03 Renegade with a manual ****** and a 3.7. Runs but runs pretty poorly and I have decided to fix it and start a new project...possibly even sell the XJ. Getting ready to determine if I need to fix the engine or just get a reman. I got this unit for almost nothing so I have a nice budget to work with. 210000 miles. Seems like it needs heads at minimum. What's been the experience with high mileage 3.7's?

 

[rcjohnson]

I would start with changing all the fluids, the plugs, clean the intake. All that routine maintaince stuff that probably wasn't done. Also run some intake cleaner through the gas.

 

[ktmrider]

I would start with changing all the fluids, the plugs, clean the intake. All that routine maintaince stuff that probably wasn't done. Also run some intake cleaner through the gas.

Thx, we are going to do a leakdown on the cylinders and get an overall heath of the engine. Hopefully it will be some easy fixes.

 

[TwoBobsKJ]

Thx, we are going to do a leakdown on the cylinders and get an overall heath of the engine. Hopefully it will be some easy fixes.

If the engine flunks the leakdown test a low mileage swap is an option using an engine from another Chrysler product:

Engine Swap Overview

Bob

 

[tommudd]

Like mentioned above check it all over good, could be it just hasn't been goone over with fluid changes/ plug shanges etc for 40-50,000 miles. Mines at 211,000 and runs as good today as it did new.

 

[ktmrider]

If the engine flunks the leakdown test a low mileage swap is an option using an engine from another Chrysler product:

Engine Swap Overview

Bob

Wow...so the only changes are the sensor rings on the crank and camshaft. Must have changed computers later..what year was the cutoff? I got a bargain even if I have major damage..but I'm hoping I got a steal.

 

[ktmrider]

Like mentioned above check it all over good, could be it just hasn't been goone over with fluid changes/ plug shanges etc for 40-50,000 miles. Mines at 211,000 and runs as good today as it did new.

What clogs up on the intake?

 

[tommudd]

What clogs up on the intake?

Driving around like Grandma Moses , never getting it fully warmed up ( i.e. short trips all the time) 3.7s like to be stretched out every now and again. Mine hits 5000 rpms at least 2-3 times a week, hit 100 MPH on a very recent trip showing a new JK that they can't run with mine :icon_lol:
Use copper core plugs only, change every 30,000 miles and RUN THEM!! :happy175:

 

[LibertyTC]

Woh 100 MPH in a KJ ..You are scaring me Tom! I never have had mine above 80!
What rpm did you hit at 100 MPH when you are re geared...
Those kind of runs must clean out the Kj good!
Always wanted to pull a plug before and after a 100 mph run, to see if it actually cleaned it up!
BTW its copper core plugs...not sore....just in case some one asks what a sore plug looks like !

 

[ktmrider]

So is it the intake itself or the throttle body that clogs up?

 

[TheBlueKJ]

I never have had mine above 80!

Really? I've had mine at 100 with a bad rear UCA. Now that was sketchy lol but the Liberty is fine at those speeds nothing to be scared of

 

[TwoBobsKJ]

Wow...so the only changes are the sensor rings on the crank and camshaft. Must have changed computers later..what year was the cutoff? I got a bargain even if I have major damage..but I'm hoping I got a steal.

Changing the rings is to accommodate the change in computers from the 02/03 3.7's and those from 04 and later. So you can use a long block from any Chrysler product up to at least 2011 but I'm confident you could use one up to 2013/14.

As noted in the linked thread, all manifolds, oil pan, motor mounts, etc etc need swapped over but if you're reasonably handy it is a straightforward swap. Use the kit from Engine-Guru.com so you're only breaking down one block.

Bob

 

[LibertyTC]

So is it the intake itself or the throttle body that clogs up?

Cabon builds up if you dont blow the dust out frequently. Throttle body,IAC, back side of valves, I think you get the idea. I use Chevron Techron Concentrate a few times a year and while that in the fuel, a good hwy run with a few pedal to the metal 4500 rpm runs will burn some of it off.
I will clean the throttle body & ports with spray cleaner once a year as well.

 

[ktmrider]

Thx guys! Anyone ever poured Seafoam straight down the TB with it running? I did that on the XJ a couple of times and Seafoam works really good on carbon.

 

[ktmrider]

Already been looking around and I think I'm going to install a Frankenlift with some Al's UCA's. I have a Rock Lizard front bumper on my XJ. I think I got one of the last ones he made for them. That guy is difficult to deal with but the bumper is really nice.

 

[ktmrider]

Ok got my hands on the KJ today. Limped it home on 5 cylinders. One of the heads has to be replaced. The guide that holds one of what I am guessing is a lifter is broken. I found a local set of rebuilt heads on Craigslist. So I am trying to make a deal for them. Overall its not in bad shape. The ac/heater plenum door is not working right, shocking. I swear every Jeep product ever made must develop that problem. The only thing I am concerned about is the drivers seat. Its kind of jacked up and I hate trying to fix seats. The motor is working but the switch is missing parts and is detached. That side trim piece is detached and the recline lever is missing. Going to see if Jeep still has parts. May just try to find a salvage yard complete seat.

 

[ktmrider]

Made the deal and got the heads. So the plan is 2 rebuild heads and bolts. New water pump, belt and hoses. Going ahead and servicing the ******. Its an auto btw, not a manual. Looked around and the odds of getting a Renegade seat are not that good. So I will tackle fixing the stock seat. What's the story on the bored out throttle bodies? Do they seem to really make much difference?

 

[ktmrider]

Got the heads off. Found what was wrong with the heater controls...vacuum lines left off from previous work. Zero sludge in this engine. Has a new radiator, but the evaporator was just laying there not bolted up. All crankcase vent hoses are dry rotted. For the most part all the major components look ok.

 

[CalcityRenegade]

Woh 100 MPH in a KJ ..You are scaring me Tom! I never have had mine above 80!
What rpm did you hit at 100 MPH when you are re geared...
Those kind of runs must clean out the Kj good!
Always wanted to pull a plug before and after a 100 mph run, to see if it actually cleaned it up!
BTW its copper core plugs...not sore....just in case some one asks what a sore plug looks like !

I don't blame you with the RCMP over there LOL, They are just waiting to take people's vehicles away, I have lots of rural areas we tear up, Even the Gravel Road Cops here are less intense although they do like messing with us.

 

[ktmrider]

BTW I went by the local Jeep dealership and they have boxfuls of Liberty trailer hitches for the recall. My Vin came up for a replacement.