The '90 doesn't have a radiator cap; just the reservoir cap. Is that the one you say should be left open until the thermostat opens?

Oh, and the story about thermostats missing causing overheating started with the stovebolt chevvies in the 50's. With the thermostat out, water flowed through the radiator too fast to properly conduct heat, thus the overheat.

 

Still wondering how u couldn't get water into the bottom of the motor.

 

I've had some good luck squeezing the lower radiator hose while filling and warming up.
Although it's messy, on a 1990, I loosen up the rear water temp gauge sender on the cylinder head until fluid comes out. (does not apply to later models).
My 1990 is a real bear to get all the air out.

I've tried the following with some limited success. It will only work on an open system. Fill system with as much coolant as you can first. You really need two people, one person to shut the engine off if fluid starts getting thrown everywhere.

 

I never have understood the so called XJ "burping" problem. If there were an issue with trapped air, Jeep would have installed a "air bleed" screw. Coolant/trapped air flow to the front of the motor (the highest point) the moment the motor is started. Just fill it, start it, let it idle with the bottle cap off (closed system) or rad cap off (open system), keeping the bottle (closed system) about 1/3 full all the time while idling or keep the rad completely full all the time while idling. Install a new bottle/rad cap after the stat has opened. During each weekly hood opening (motor COLD), check coolant level in either the bottle (closed system) or the rad (open open system)

(Hey Mr. cruiser, is it really difficult to burp a Renix?)

 

I meant into the block (brain f**t). I followed your instructions and 'burped about a gallon and a half in through the overflow tank, 1/3 of a tank per start.

No leaks that I can see, oil's fine, etc., but the p.o. had apparently just replaced the t-stat, and hadn't fully filled it up.

Temp outside is 101 right now, and I just let it idle for a half-hour. It stayed just below 210 (just like my YJ), and drops below 200 when I run it up to 2K RPM. Before the burp, it overheated and boiled over all over the place!

So far after spending $700 for the rig, I've replaced the alternator and fuse link, and burped it! It hasn't been used since 2003, and except for the headliner, an easy replacement (relatively), and probably a Cat, I think this will go to my daughter as a daily driver.

Really appreciate the help, djb383, as this is my first time with a "Closed System".

 

Look at the bottle frequently and make sure the bottle is never empty. I don't have XJ with a closed system but I do have a '06 Saturn and a '09 Toyota, both with closed systems. Can't get much easier to check coolant level than on a closed system, motor hot or cold. Kinda of a hassle checking coolant level on a open system as the motor should/must be cold so the rad cap can be removed to positively check coolant level.

 

Gotcha! I'm all over it, and I firmly believe your sig line!

Thanx again, and I owe you a cold one!

 

I replaced water pump, clutch fan, radiator hoses and everything. Still overheats to 230-250 degrees... I have a 180 thermostat and it’s 95 degrees outside. I checked to see if I have any cracked cylinders and I’ve got nothing... would it be easier to replace the whole radiator with new fans? Or just get some upgraded clutch fans and electric fans?

 

That's pretty hot. You'll have to do a leak down test and verify you're actually seeing those temps with a temp gun. Please list all the actions you've taken as previously posted by others? How did you check for bad cyl head? Others will most certainly chime in. Good Luck, those temps if real are not good.

 

The stock Cherokee cooling system works just fine for people crawling in traffic in Phoenix in the summer. Unless you are doing a lot of rock crawling, there is no reason to upgrade anything unless you like breaking things that aren't broken. This forum is full of threads of people who spent a thousand bucks and more trying to "fix" their cooling system with expensive parts, and failing to solve their problem.

If it's not cooling, something is wrong. Find what's actually wrong and fix it.

And stop dragging up old threads!

 

Sorry to **** in your cornflakes old dude. He asked a question, let's help him. If you're not going to help, go back to your cave and get some more sleep.

 

I will add that The Stock XJ cooling system is more than upto the job of cooling the stock 4.0 in ANY normal driving and wheeling situation.
This and 100 other forums are littered with stories of people buying the latest "Racing thermostat, radiator, 100 GPM Kooler water pump" trying to solve an overheating issue.
And in the end routine maintenance was the issue. And the 4.0 would not run cool UNTIL they pulled off the $500 of aftermarket crap.

I think Mark was trying to save some folks some money, Time and heartache.

 

I did help him, if he's willing to listen.

Telling him what fancy parts to buy that he doesn't need is NOT helping him. It's being stupid.

 

Hello and sorry this question is irrelevant to the post but how the heck do you post something on here? Please help me and thank you very much

 

Well, thanks for the honest question! Welcome to the forum.

Here ya go:

1. Figure out what kind of car you have. For example, a lot of Grand Cherokee owners post in the Cherokee section. Different cars. Then there are the later "Cherokees", which aren't really Cherokees but Chrysler calls them that.
2. Figure out what kind of question you have. How to fix something, or diagnose a problem? We have technical sections for each vehicle, and (sometimes) a "modified" section for some of the vehicles. Pricing of vehicles, or general chit-chat? We have a chat section that applies to all vehicles.
3. Once you find the right section of the site, find the "New Thread" button on the upper left.
4. See below for some relevant pics, and some nonsense just 'cause.

New thread button. Push the button, Max!




Find your home!




Something you probably want to do - turn OFF "related threads". It's in your profile somewhere.



'Nuff said?