AZJeff

You can remove and clean the lifters (and put them back in the same holes they came out of). If you have lifter tap, how sludgy is the engine to begin with? Are the oil passages all gunky? 195 is what is intended to achieve the leanest burn for emissions. It also extends spark plug life and reduces carbon buildup. Don’t trust the temp. Gauge to be accurate. It may actually be running at a temp higher or lower than indicated. i will defer to others about any 4.0 with studs/nuts in lieu of bolts, as that is new to me. Yes, the through bolt is the pivot bolt.

Yes, a voltage drop WILL generate heat, assuming a constant current condition (which is usually the case).

I would NOT recommend changing the valve lifters unless you are changing the camshaft as well. Each existing lifter and it's matching cam lobe have worn into each other quite nicely, and changing one half of that now "mated" pair can invite trouble for the already used half (the camshaft). DO NOT use a 185 thermostat. The engine (and all associated emissions systems) were designed to run at 195*. By the way, you say "head studs" in your post. I was unaware of any of the years of the 4.0 in OEM trim that used anything but those special torque-to-yield head BOLTS. The brackets that attach the motor mount to the block are torqued to 45 ft-lbs. The ones that attach the mount to the bracket are as follows: 30 ft-lbs for all fasteners EXCEPT the mount through-bolt, which is torqued to 48 ft-lbs.

Not true. High current plus high impedance WILL translate to high heat at the interface of the two surfaces.

Not only may it not charge the battery, but it might create a high resistance connection that will lead to overheating of the connection and a possible fire. Fix the loose terminal to avoid a “carbacue”

Yeah, I know that is the case in most states. However, here in AZ, there are PLENTY of areas out in the boonies where you want all the light you can get. So my aux. lights are set up so that I can switch on the high beams, the light bar above the front bumper, and some driving lights mounted on the bumper. It probably violates state law about maximum candlepower, but I also use them intelligently--out of the open road with no oncoming traffic. But we all know of nimrods that run around with all sorts of auxiliary lights that blind other drivers, as well, so there is THAT consideration.

When I run auxiliary lights, I prefer to tap into one of the front parking lights for control line power for the relay. That way I can run the aux. lights any time the parking lights OR the headlights are on. Just another way of looking at things.....

More questions/suggestions to help narrow it down: 1. you say "take it out of gear." Does this mean just push the clutch in, or actually shift to neutral and release clutch? Do this both ways and report results. 2. additionally, when you push clutch in (and leave it in gear), rev the engine to the "magic" 2K to 2.5K range, and see what happens. They do the same with the trans in neutral, and the clutch engaged.

What happens if you shift to neutral and let the engine drop to idle while it's making the noise at highway speeds? Does it go away, or stay the same? That test will tell you if it's driveline or engine related.

Nice work on writing up the facts that most Jeep owners don’t understand about their HVAC system👍

I had this problem on my 1991 F150 when I owned it. I ended up drilling out the rivets that attach the aluminum arms to the steel mounting brackets, and replacing them with stainless steel bolts and “nylock” nuts.

I might be wrong, but I am pretty sure that if anyone had found a taillight housing that would fit into the existing MJ space (without welding/cutting), it would be all over this forum. Until someone figures that out (or comes up with some kind of "drop in" adapter that allows the use of smaller taillight from another vehicle), using old MJ used taillights of varying condtion is the only option. If I was desperate for new taillights, and couldn't find any decent ones for an MJ, I would save my pennies and have the bodyshop weld up the existing opening to take XJ taillights. I figure that would cost $1000 or more, including paint, so it's a true act of desperation.

I agree with this assessment. The complexity of welding in a large irregularly shaped piece outweighs the benefits.

Thank you, sir, that is perfect!

Does anyone know the "official" specifications for the wheelbase length of a MJ with the "short bed"? I am looking for something more than just "110" or whatever. I am hoping someone can tell me it's supposed to be "XXX inches, plus or minus Y inches"

Since you probably will not find a Comanche-specific harness, I would just hard wire (with solder and heat-shrink tubing) a trailer connector into the back of the vehicle. Stay away from butt-splices, unless you can keep them from getting water into them from under the vehicle. They tend to oxidize and become intermittent when exposed to a moist environment.

The ZJ and KJ factory drum type parking brakes work as good as any, provided they are adjusted properly and free of mud and other crap. The factory would not have installed an ineffective parking brake. Most of the issue is people using worn out junkyard parts in their conversions, and declaring all drum parking brakes junk.

That is completely dependent on where the vehicle lived. Here in AZ, the nuts come off the studs on ALL the XJ handles no sweat. I would guess up in your area, the rust on the studs makes it problematic.

Given the non-pressurized nature of the oil distribution in the rocker arm, I doubt it makes any difference. The FSM makes no mention of orientation consistency, either.

AGREED. They are cheap, and if you own/fix old Jeeps, they can help you identify suspicious noises that seem to crop up.

Here is my suggestion (having been in your shoes): Most of your decision should be based on the compression test and oil pressure. However, since you state that you have a trashed valved on one cylinder, at least one of your six compression test readings may be invalid. If compression on 5 of six is pretty even, and within acceptable limits for age, it's probably a good bet the valve is the cause of the low reading on the remaining cylinder. Once the head is pulled to deal with the valve issues, you can visually examine the low cylinder and confirm it's walls are smooth, and the piston doesn't rock too much. That would indicate that a refreshed head would make all things good in the cylinders, and that would be the route I would do on the top. If the oil pressure is within the normal range, don't worry about the bottom end. (This assumes you have no funky knocking noises right now.) If the bottom end leaks (pan/RMS), then drop the pan to fix that, and for less than $50, you can throw in a high volume oil pump that would boost pressures on loose bearings a bit. If the bottom is NOT leaking, just leave it be, assuming the oil pressure is OK.

But after the body refresh in 1997, only black handles were offered on the XJ.

I have had this happen as well. If the threaded portion of the ball stud (as that is it's name) is not too mushroomed, you can grind a chamfer on the first thread or two to allow the castle nut to thread on. A dremel tool is your best bet for doing this on the car. If you get to the point where the grinding enters the area where the nut will be on the threads when fully tightened, then it's too damaged to be reused, and a new tie rod will be needed.

You are my new best friend. THANK YOU!!

I am guessing the part numbers are different for the early and late switches. Does anyone know what are the correct part numbers are for a 2001 XJ cruise control switch group? I guess I could ask the dealer....