Right now I have to decide if I want a radiator from Oreilly's or autozone or similar, or get an all-aluminum one ordered from a website. The former means I will have it repaired in time to go to Colorado, and the later means I will have a better radiator for about the same price.

I ordered a premium radiator from Oreilly's. It's a 2-row, copper core and has plastic sides, and it cost $200 after taxes. However, it was damaged in shipping and the plastic side was cracked at the filler neck. I returned it and got my money back and had them order a new one that will be in today.

I think that if the new one is not cracked then I will use it. The old radiator that failed on me, it was the plastic side that burst open, but it was five years old. I don't know if I'll have the jeep for longer than that so I think I will go with that one as my short-term goal is to drive it to Colorado and put the $1500+ in upgrades to their intended use, and my long-term goal is to get the Jeep to 300,000 miles.

Here's the receipt from the last time the radiator was replaced, over five years ago. It says it's a radiator for a right-hand-drive Post Office vehicle.



Removing the old radiator wasn't that hard.



However, I couldn't remove the upper transmission oil line without bending the metal tube so I just cut it off. The lower tube I just pulled off and I think I broke it.



So my solution was to install an auxiliary transmission oil cooler. I got the "medium duty" one from Oreilly's for $50 though, now that I think about it, maybe I should have gone with the heavy duty one because it was only a few bucks more and overkill is usually better than underkill.

I'm mounting it to the front of the AC condenser. It will be visible behind the grill but it's the best place to put it. It was pretty easy to install. It came with rubber hoses and hose clamps to connect it to the factory transmission oil lines.



While waiting for the new radiator to arrive, I installed the steering box spacer and steering brace. It was a great time to do it as the lack of a radiator provided some extra elbow room.

 

Premature wear of your motor mounts and run the risk of the mechanical fan hitting the radiator.

 

Nice! i think im gonna pull a trans cooler from the JY and toss it in my XJ as we,, since i need to replace the lower tranny line.

 

It solved two problems at once. First, I couldn't get the old trans oil lines off the old radiator that cracked and left me stranded two nights ago. And 2nd the new radiator had the hookups for the trans oil lines on the other side so I would have had a problem there.

Some people say it's better to have the auxiliary cooler run in series with the stock cooler in the radiator because it will have the added benifit of heating up the oil to 210 degrees which might help in winter. I'll keep this in mind if shift performance goes down next winter.

 

I would replace the tstat if i was you. Cheap and easy and i always replace them when anything gets hot or overheats. Just a suggestion. Good luck on your trip.

 

Your old receipt says the radiator was for a cherokee EXC RIGHT HAND DRIVE etc etc where EXC means EXCLUDING. Just an FYI

 

Where to begin...

The new radiator is installed. Copper core, two row. I put a Preston flush additive (not the kind with stop leak in it) with straight distilled water into the cooling system to clean it out real well. It says to drive it around for a few days then drain and flush it.

Then I trimmed the fenders. Followed the recommended steps for cutting in front and slicing and bending in the rear. Just a minimal amount, didn't even need to remove the wiper fluid bottle.



One thing that I did different that most was instead of removing the plastic inner fender cover, I kept it there and zip tied it to the old fender brace bracket thingy to keep it in place. Then I used an old 4-wheeler trick to use zip ties to "stitch" the inner fender to the bumper and thus avoid the problem of having the horn and a few other things exposed to mud and crud.





Not perfect but I think it will do just fine.

Then I put in new engine oil and transmission oil, and went for a test drive.

I got a little carried away on the test drive...


The good news is we didn't get stuck, although I learned how ****ty clay mud is. It was nasty.

The bad news is it overheated. It happened on the highway on the way to the little trail. I know that it really did overheat and not a bad temp gauge because the water was boiling into the overflow tank.

The next day I replaced the fan clutch hoping that that was the problem. Then I drained the water + flush additive out of the radiator and this is what came out.


With a new fan clutch, new 50/50 coolant mix, and a bottle of Wetter Water in the radiator, I was feeling pretty confident I had the overheating problem fixed!

Wrong...

10 minutes on the highway and the temp starts to creep up, just like it did before. About halfway between 210 and the red tick I pulled off the highway and that's when it really boiled out of control. Boiling water doesn't cool very well and it becomes a feedback loop. I turned off the engine for five minutes, turned it back on and let it idle for a little while to circulate the coolant and it didn't take long for it to go back to normal temp.

Drove back extra slow and it was fine..

That all took place about a week ago. I obviously did not go to Colorado as planned.

But, I have a new water pump, and I'm optimistic. I will drive this turd to Colorado if it's that last thing I do!



(at least it looks good)


OOooooooooh.

 

Only starts to heat up after 10 minutes of highway speed driving. Driving around town all day and it's well below the 210 mark. What do you guys think is the problem?

Hopefully one of these products and a good flush will due the trick but I have a feeling I'll need to upgrade the cooling system somehow to compensate for the increase tire size which is what I'm worried has caused this problem. I don't know...

 

At least I have this fancy picture of myself working on my Jeep

 

Checking to see if I have a blown head gasket before replacing the water pump. This morning I tried doing the "block test" (that's what Oreilly's calls it) to check for combustion gases in the coolant.

But it was a highly flawed test, at best, and at worst it was a completely worthless experiment that spilled coolant everywhere. The problem was that coolant was rising into the test tube and mixing with the test fluid.



You can also see that the coolant/fluid in the test tube is a little bit yellower/browner than the coolant showing in the filler neck of the radiator. The blue test fluid is supposed to turn yellow in the presence of combustion gases.

Then I started seeing little bubbles rise up through the coolant/fluid, so I took this short video:

The engine was warming up but was not yet fully warmed up and the electric fan had not spun at all. The coolant was replaced exactly one week ago, and I did my best to bleed air out of the system by idling the motor with the rad cap off and also squeezing the top radiator hose with the cap off.


What do you guys think?? Should I try again but with much of the coolant drained so it doesn't go into the tube?

 

If you're still thinking about doing this, make sure you place it on the passenger side where the belt-driven fan is. I'm going to have to move mine over as I placed it in front of the electric fan which isn't on most of the time. Big mistake!

 

After it overheated on the highway, did you check the rad hoses to see if either one of them had collapsed?

 

No I didn't check the bottom one, but I'm just going to replace it anyways to rule it out

 

Did you replace the thermostat when you did the radiator and fan clutch? Highly doubt it's the water pump. If the coolant is bubbling like you showed and the tester is as yellow as it looks in the picture you may very well have a blown head gasket or cracked head .

 

Good question. Had that problem. Found a hose with a spring at the JY. Worked. Also helped on flushes.

​​​​​​​Sales guys always say its either mods or maintenance (or these days, mileage).

​​​​​​​Seen where engineers say the 2.8 V6 system evolved insufficiently for the 4.0.
​​​
Check out https://jeepexhaustadapter.com/

​​​​​​​Avoids brain damage if you swap certain heads.