89 MJ

September 2025 - 86 MJ Flatbed 2.5 Owned by @jeeper_chiefb Build Thread- Year/Model - 1986 Comanche Drivetrain- 2.5L, AX5, NP231 TeraLow 4:1 gears and SYE, Currie high pinion 9" front axle, semi float 9" rear, 4.88 gears, ARB air lockers Cooling- aluminum radiator, new water pump, 195 thermostat Electrical/Ignition- reman ECM, new ignition module, cap, rotor, wires, plugs Suspension/Steering- SOA rear, 4" Skyjacker coils, ACOS, Rancho shocks, Teraflex control arms, Iron Rock track bar, 1 ton TRE steering Interior- Corbeau Sport seats on Corbeau brackets, late model XJ console, Barnes4wd support bracket, custom leather shift boot, ashtray switch panel Brakes- drilled slotted 11" rotors, XJ calipers, Quick Performance rear disc kit, all steel braided lines Lighting- rear 25" light bar, 6x LED rock lights, Baja Designs Squadron lights in grille, 6 switch pod controller Exterior- custom LWB flatbed with a 1000lb bed crane, 48" HiLift jack, 3 ton offroad jack, 5 gallons fuel and water, vice, custom YJ bumpers Wheel & Tires- 35x12.50 Yokohama Geolander X-MTs, 17x9 Sidetracked Offroad beadlocks Misc- dual winches, Warn 9.0RC front, Smittybilt 12xrc rear Best MJ story- I bought this truck because I love old jeeps after owning multiple CJs, YJs and XJs, and I had the intent to build a light duty recovery truck. When I got it home my 15 year old daughter fell in love with it and wants to make it her first truck. We'll see. CC is Awesome! Why?- I have many future plans for this little MJ; exocage, floor boards, LS swap, long arms, frame stiffeners.... Everything I plan to do has been documented on CC by someone before and is great motivation for what can be done with enough effort. There is something about this MJ that I really like. Congrats on the MJOTM!

Ah yes, welcome to Jeep ownership

I’d remove the supports, weld in new keyparts floor pans, then put the supports back in, after they were sandblasted and primed with a weld through primer.

Some AMC goodness here. There’s a vintage themed diner in Tucson called Little Anthony’s in Tucson that has the Pacer from the movie Good Burger at it. @eaglescout526 was in town, and he got to put some miles on this fine specimen too. Always good to chat with friends, especially about AMCs!

I ordered the Dorman one and used the cap a few years ago. My tank let go, it wasn't the cap that let go from the pressure. That could've just been a bad tank though.

I’d start by double checking the intake and exhaust manifold bolts. They have a tendency to loosen up over time. Id also make sure that the IAC and TPS are functioning correctly. Just because they’re new doesn’t mean that they are good.

Most definitely! Also, I got a thumbs up from a guy in an MJ yesterday, which was super fun.

They were such a high performance racing vehicle that the 4.0 would've been too fast for the SCCA racing, so they had to use the 2.5L instead. Or at least that's my story and I'm sticking to it

Well, two(ish) week update of driving the car. It's been a daily driver for about a week and a half and I am very pleasantly surprised. It gets warm if you have to sit through the same stoplight multiple times, but otherwise she lives between 195 and 210 degrees. It is absolutely hilarious to park this old thing next to all of the fancy pants cars that a lot of college students have. Or even at apartments, the thing sticks out like a sore thumb One of the best parts is how comfortable in the car. I can judge it well and get close to stuff and I feel safer in it than I did in my more modern school vehicle. Best part is everyone's reactions to the car though. Almost every day that I have driven the thing, someone either asks what it is, thinks its super neat, or has stories about one from 30+ years ago. It has been a ton of fun.

Same experience first. My truck would need to sit pretty much all winter for me to need to prime the fuel system. And I've never seen a fast starting race car either...

IF I recall correctly (that’s a big if) it’s because the computer doesn't remember which cylinder is supposed to fire next after being shut off, so it needs to turn over for a while so it can determine which cylinder to fire.

Renix era Jeeps take longer to start. All three of my Renix MJs took longer to start than any of the GM TBIs I’ve been around.

No replacement for displacement. V8. Surf or turf?

Yeah, best to steer clear from doing that on dry, hard surfaces. That’s a good way to break stuff.

Are you testing this on dry pavement?

There should be studs with nuts on them every few inches inside the wheel well.

I’d do a new fan clutch for the mechanical fan, a late model XJ efan, and a Mishimoto radiator.

Score!

Is it just as bad in high and low range? My truck has rubberized undercoating, then the floor, then Chassis Saver paint, then Dynamat, and then carpet and it doesn’t seem to get very hot. The farthest I have run it recently is about 90 miles each way though. I wonder if it would be worth trying 10W30 in the trans, per Chrysler’s TSB or whatever it’s called.

I’d agree with this conclusion. Maybe I’m misremembering, but I think Flowkooler has a lifetime warranty.

Interesting. I’d be suspect of the cooling fans then. Any chance you can dig up info on them? Also, what kind of driving are you doing when it overheats? Mostly stop and go traffic or cruising?

Did the engine get new gaskets, bearings, and rings? Or did it get all of the machine work done and proper cleaning procedure too? I just checked out your build thread. Looks like you went with a flowkooler. I have the same rad and water pump. I would also be skeptical of the triple electric fans. Rarely does an electric fan flow more than a clutch fan. And if they’re cheap fans, they probably don’t flow nearly enough.

Verified with an infrared thermometer or just going by the gauge? What brand water pump? What size tires and gears?

Old GMs, and likely others, used an oil filled shock instead of a gas charged shock. I would think it’ll be fine.

Unfortunately, I suspect a lot of those people haven't even seen a long bed with a roll bar, let alone own one. I would guess that you got so many views because of the title before people realized that this was a wanted ad and not a for sale ad.