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New Old Member & List of Problems


NAXJA Forum User
Hello NAXJA. I used to frequent the site many, many years ago under similar handle but couldn't remember my login and had to create a new one.

As the name implies, I have a well-maintained 1998 XJ limited that I have been the primary driver of since it was handed down to me in 2000. The vehicle has spent the better part of the last ten years in storage with infrequent use. My father was employed with Mopar for much of that time and the vehicle saw regular service with only OEM parts. Where there was the opportunity to do so I have used the chance to replace broken or worn parts with aftermarket upgrades including aFe intake, '99-Up horseshoe intake manifold, Banks torque tube header, MagnaFlow cat-back exhaust, and Old Man Emu heavy duty suspension system. I recently constructed a steel building on my property where the vehicle now resides and I am finally getting around to addressing all the mounting repairs to get it as close to cross-country driving shape as can be expected.

That list of problems includes:
Cracked header (have replacement in-hand).
Occasional overheat.
Dimmer switch (dash lights on high or not at all).
Driver side rear power door lock intermittently not working.
Driver side leather seat crack repair (crack repaired, need to dye match).

Optional upgrades on the radar:
Gasket match intake manifold.
Head pipe matched to cat-back diameter.

Since I have to dive into the engine bay to swap the header anyway, I was thinking of crossing a few items off the above lists and am looking for insights as to process and whether they are worth it or a waste of time/$. For instance, is a FlowKooler or Hesco water pump advisable? What radiator, if any, would you recommend? How about the Hesco thermostat housing and Stant t-stat?

Also, in regard to the electrical items, I am hoping you all could weigh in on how best to fix these items. Is a new dimmer switch necessary or is it just a matter of cleaning the contacts? And, is the intermittent door lock an actuator or perhaps something else - how best to diagnose?

Good to be back. Thanks in advance for any assistance!
Welcome back!

There's a big radiator thread over in the Modified tech forum that should have lots of info for you to digest on that front (https://www.naxja.org/forum/showthread.php?t=1150722), but a number of people seem to be having good luck with a fairly mundane two-core unit with plastic tanks - possibly an Amazon item.

On the water pumps, I seem to recall both those names being around in the past but I'm not sure about these days. I also seem to recall several people reporting better results with the stock pumps rather than the high-flow ones, but I don't have any direct experience myself.

More info on the occasional overheat condition would help narrow down what to look at.

On the intermittent lock thing, is the actuator solenoid intermittently not firing, or are you getting the "chunk" noise but the lock mechanism doesn't actuate properly? I've occasionally seen the rear locks on my '92 not actuate fully, but usually giving the mechanism a thorough spraying-down with white lithium grease tends to loosen things up. if you're not hearing the actuator fire, maybe the switch itself is acting up?

You may want to look into adding a relay harness for the headlights as an "upgrade" - the factory routes all the power going to the low/high beam filaments through the headlight switch in the dash; that's a long run through small wires for that much current, and a fair bit of stress on the switch itself. Adding the relay harness would reduce the load on the headlight switch to only what's needed to activate the relays, effectively eliminating any stress on that bit of the switch.


P.S. You mentioned repairing a split in the leather seats - was this a DIY process? My daily driver VW has a small split in the driver's seat that I'd like to address; I'd be interest in the product you used or the writeup on it so I can see if it's something I'm comfortable tackling...
Having been in Az for the last 60yrs I've grown quite adept to overheating issues. For XJ'S I really like the Hesco pump (have 2 to date), didn't have good luck with the flowkool. The t-stat housing from Hesco is good deal if you do not have the tooling to do it. I didn't take any chances with a stroker so I got a Griffin radiator but it was not cheap. All together I'm at 8+ years with no issues.
Something else you may want to look into doing is a fan override relay setup. Either diy or get the k-suspension kit.

Also look into Jeep Cables battery cable upgrades
If you're taking off the header and intake already, maybe take a look at the motor mounts and think about replacing those while you're there. I don't know if you plan on wheeling this thing or keep it stock but there are more robust aftermarket options that are less prone to failing.
If auto, I'd add a trans cooler. I did but a water pump from HESCO same years back. It was a Flowkooler. I think their present offering is their vein type pump. I would recommend an aftermarket motor mounts if added a HD radiator. I use the 3 row CFS. Not saying it is the best. I do have a HESCO thermostat housing. I rounded up the edges on it. Then I took a stock thermostat housing and did the same thing with a rotary bur.
I also like a ceramic coated header. I use a Doug Thorley. Also, I do have the H4 headlight upgrade with an upgraded harness. Probably 4X the light of stock headlights.
The 99+ intake might add +5hp to your present setup. Can't say I noticed the power unless I was going up grades on the highway. Regearing helped a bunch.

Also, I have tired the Hi-Flow thermostats. I had a Mr. Gasket come apart on me. I don't know what other one I used. It stuck open. I have tried Robert Shaw in the past. They are being made again. Also, Stewart is the extra option from the same company. I think Flowkooler. I think for high flow water pumps. I'll probably use some Carols (NOS) I have on my mini stroker.
Also, I recommend using a MOPAR clutch fan if you use a HD radiator. With an aftermarket it gets real close to the radiator. Yes, I took out a radiator. Also, the reason for aftermarket motor mounts. I have Brown dogs. I also like to use MOPAR water pumps.
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Thanks for the pointers, everyone. I will go check out the radiator thread and see what I can glean from there. Glad to hear the Hesco products get decent reviews. I will also research the battery cables and headlight harness.

As for the occasional overheat, it is the usual phenomenon with XJs -- upper 80s/low 90s ambient temps, coming off the highway, sitting at the exit w/ a/c on waiting for traffic light to change and watching the temp gauge creep up. Nothing deadly, more disconcerting. Have flushed the radiator within the last year or two. Didn't notice anything off.

Will need to dig out the stethoscope and listen for the lock on that door in particular. It's pretty audible in the cabin with all the actuators firing in unison. It *doesn't* work maybe 80% of the time but it does work sometimes. Makes me think it's electrical. Will check and report back.

The seat repair job was a DiY courtesy of the neighbor. He used to own a automobile restoration franchise where he was subbed out by used car dealers to spruce up their auction hauls. He had some compound lying around and whipped it up to fix the cracks with a heat gun. I can inquire what was used and post here.

She's a limited so came from the factory with the tow package including transmission cooler. Curious on the parts list for the H4 headlight upgrade. Been running Sylvania silver stars but still no where near modern day standards.

Thanks all!
Radiator is probably half clogged, typical on an xj. On an all stock jeep, a cheap spectra radiator, new stant super stat, and a new fan clutch and a standard water pump will be all you ever need.