Airborne Janitor

Took her out on the highway for a bit today, stayed pretty cool around 190-200. But as soon as I pulled off the highway and stopped at a light the temps would rise back into the 220 range, until the RPMs started moving again. The 4.0 is running around 800rpms when stopped in D, and it seems any times revs are under 1000 the needle on the temp gauge rises. Think I'm gonna go ahead and order that Flowkooler water pump. I think burping the system at the temp sensor helped a little.

Got some painting done...

So on the drive home tonight I took the state roads, average 50-55mph. Stayed right under 210* unless I was stopped at a light, then it would go to 210, then drop back down on acceleration. I bled the air at the temp sensor tonight, the truck ran right around 185-190* for 30 mins. After turning her off and tightening the sensor, I turned the vehicle back on and the gauge was at 230*, then dropped down after a few mins. Will grab my temp sensor tomorrow and report back.

Water pump was replaced 7 years ago. I am contemplating getting a flowkooler replacement, I've been running one in my XJ for years with good luck. I need to get my temp gun to confirm temps, but I drove this truck last year without issues until the head gasket started leaking.... I'm running 3.55 years with 33s which sucks but is doable, I have 4.56s in a box which I'm going to install once I fix this overheating issue. I'm going to try burping the system again at the temp sensor in a bit.

Gotcha. Ended up burping the system last night by popping the radiator cap and letting her run for 30 mins, no issues. 50 min commute this morning, temps stayed at around 190 then after 30 mins started to rise. I stayed off the freeway and opted to do the stop and go drive through town. Temps would go up to the 210 range when stopped at lights, then drop to 190 once I hit the gas. Made it to my destination and the needle is pegged right around the 210 mark when parked. The gauge seems to be very sensitive to RPM changes, the lower the revs the more the temps want to rise it seems. Water pump possibly?

My truck sits 2" higher in the back, I parked it on a decline in my sloped driveway, and it still made a huge mess lol. How high does the motor have to be for this to work without losing half a gallon of coolant?

I'm assuming this means popping the cap off the radiator, letting it run with the heater on full blast until it reaches operating temps?

Just started her up to drive home and now the gauge says 180.....

Presumably the shop who has done the work did it, especially after the head rebuild and thermostat replacement..... So the efan just shut off, even tho temps are at 210 right now. If I turn on the defroster it will start up the efan again...now temps are under 210 and the efan is completely off....

Currently sitting in a parking lot with the motor off waiting for it to cool off, temps around 240*. Drove her on the freeway for a little bit getting up to speeds of 75 to see if it would cause the motor to run warm. Probably after 15 mins the needle went to 210 then started to creep past it. Pulled over at the next exit where the needle continued to rise until almost red. Efan is currently running and spinning clockwise pulling air from the radiator to the motor. Temps are starting to cool, no coolant spraying out the overflow...

No I'm running the stock fan clutch and a stock 97+ e-fan (instead of the renix fan) that's been rigged up to come on at 185* at the t-stat housing instead of the radiator. I have a Renix motor converted to an open cooling system, should have mentioned that too.

Truck has no AC so no condenser, there's a tranny cooler but those are small and not hurting anything. E-fan kicks on at 185* and stays on until temps drop.

Water pump was replaced 7 years ago with a Gates unit, has less than 15K miles on it. Hoses are good, no heater control valve.

Here's a pic of the temp gauge when I was stopped yesterday after pulling off the freeway.

1989 4.0L currently running a Mishimoto 3 row radiator, new thermostat, new fan clutch, new OEM temp sensor, 97+ electric fan. This is not the original motor but a Renix head on a HO block. Head gasket was leaking so I took it to a shop back in March for repair. Since the repair the truck has had intermittent cooling issues, and I'm not sure if it's coincidence or correlation with the cylinder head rebuild. After the first overheating episode it was found the electric fan was not turning on. We ended up replacing the Renix t-stat housing with an HO one and rigging a temp sensor to it that activates the fan at 185*. The fan now works but did not solve the overheating issue. Then it was found the fan clutch went bad, replaced that and it helped....for a bit. The truck is currently running a new 180* thermostat, it did have a 195* in there but was changed by the shop. The motor does not overheat everytime you drive it, it almost feels random. Sometimes the temp gauge sticks right between 185-210 and stays there. Other times it goes to the 210-230 mark and stays there. Yesterday on the freeway going 80 MPH on a 60* day I watched the gauge slowly creep into the 230 range after 30 mins of driving. Took the next exit and watched the gauge creep towards the redzone at a stop light. As soon as the light turned green and I applied gas I watched the gauge drop to around 220. It seems temps drop whenever you apply gas. I've watched the gauge move 30* cooler while driving than when stopped. I had never seen the temp gauge move around so much until after the rebuild. I've also noticed that the motor continues to get quite hot after turning it off. If I turn off the truck, then come back in 5 minutes and turn it on the temp gauge is a good 20-30* hotter than when I parked it. There was a time the truck was creeping into the redzone, so I stopped and parked it, only for coolant to be pissing out the overflow bottle minutes later. I want to say it seems to overheat more at highway speeds, but I have not confirmed this 100%. It overheats while driving, it overheats while sitting. Sometimes it doesn't overhead at all and stays below 210*. I feel like I'm playing Russian roulette with this truck when I drive it, and each time I've taken it to the same shop I feel like they're offering nothing but bandaid fixes. My MJ NEVER overheated prior to the head work. I'm hoping this is just correlation and not causation. Any ideas? Thanks.

Got the diamond plate platform cut and welded into place. Axle painted and reinstalled. In reference to a question I had earlier I do have to run some type of brake backing plate on the axle even without brakes, otherwise it creates a gap between the axle retainer plate and the seal. Tightening down the retainer plate puts too much preload on the seal and will cause it to leak without something to fill that gap. Here's the trailer jack I'll be using, the Ark OR500 off-road trailer jack. This thing is a beast.

I know right, the plate is gonna get cut to follow the contour of the frame.

Springs rebuilt with new hardware. Waiting for the paint on the shackles to dry... Rear axle prepped and waiting for paint. I was missing a few of the dual thread studs that mount the bed to the frame. They are size M10 x 1.5 x 50mm. I found some turbo/exhaust studs that were a close enough match. Got the diamond plate fitted up to cover the front bed gap. Going to weld up the floor/platform in the next few days.

Got the bed on today!

Cool to see so much interest in the project already. Got the safety chains welded onto the tongue. Had a few MJ leaf packs lying around, so I picked the "best" ones out of the bunch and separated them to knock off all the rust. They'll be getting the POR15 treatment soon. Took the Dana44 from my parts MJ and pulled the cover and the shafts. I know it's kind of a waste to have this axle under a trailer, but it was available, was already set up for spring over, and did not require any additional fabrication or money on my end. Gears and axle bearings looked good. I think I'm going to move the big drum brake backing plates over to my XJ. Which begs the question, do you need brake hardware to run the axle? Since it's for a trailer can I just shove the axle shafts back in and bolt them up? Are there any issues bolting the wheels to the shafts without a drum?

Not sure where to put this project, it is "technically" Comanche.... A few year ago I was in search of a replacement long bed for my MJ and stumbled across this deal on craiglist, a few states over in Montana. Older gentleman had pieced together the frame, long bed, and a camper shell for a trailer project, but never got around to putting the pieces together. So I took a trip out to Montana and drove home with all the parts. I'm going to pick up where someone else left off and then some...I want this to be a camper I can park at the trailhead when I go wheeling/hiking and still have several modern conveniences. Running water, propane for heat/cooking/hot water, solar panels for power, air conditioning, and a nice mattress to sleep on. I began to build out the tongue. The frame was cut right where the front of the bed is and measures 3"x7" inside the "box". Finding 3x7 tube steel was near impossible, so I found some 5x3 and 2x3 in 1/8" thickness at the local metal supplier. Because I want to use this trailer offroad I wanted a hitch set up that would articulate well. I found the Max Coupler by CU Offroad after doing some youtube research, and ordered their MC5000 50* bolt/weld coupler kit. https://www.cuoffroad.com/product-lines/max-coupler-line/ This made it a littler easier to build out the tongue and measure out my materials. The inside of the coupler actually measured out to 54*, and I ended up welding it to the tongue, maybe I should've bolted it for easier maintenance? Oh well...

Dayton makes a Big Ton replacement, part number 95-571. I run them spring over in my MJ and got like 9" of lift. Rockauto used to have them for a reasonable price but looks like they're out of stock now.

Mine rattles too. I notice if I put my finger on the middle slider glass the rattle goes away. I'm wondering if the felt-material along the sliding track has worn out...

Hey Pete I'd like to help, email me whatever to 4x4xj@protonmail.com

Saw you got your answer on another post, but there's nothing but a tube that hangs off the bottom of the canister.