river_runner81

not five minutes after starting my jeep, the temp climbs over 210*. i figure the radiator is plugged or the water pump is out. it's a closed cooling system, i put a new thermostat in today with no change in the temp. i'm goin to try to run some water through the radiator tomorrow to see if there is a plug. if not, i will assume that the water pump is shot. the coolant reservoir has a crack that i've melted back for the time bein. i've been told there is an after market reservoir that is alumminum. anyone have or heard of one? thoughts?

troy0873

have you fixed your overheating problem yet? i just picked up my first xj a 90 4l,had to drive 30 mins home and its overheating already.just wanted to know where to start

XJWife

after market that's aluminum? wonder where to find one of those??

XJWife

I found one...much more spendy than the stock plastic tank :-(

http://www.macsradiator.com/replacme...filltanks.aspx

5-90

NB: If you've overheated RENIX, you've likely developed an air pocket behind the thermostat, and will continue to overhead (leaving aside that the typical thermostat "fails closed" anyhow.)

When you replace it, drill two 1/8" holes in the flange 180* apart. Install with one hole at 12:00, and the other one at 6:00. This makes the cooling system self-purging of air, and saves you lots of trouble.

As far as what caused the overheat initially, I'd start with a flush of the cooling system (use the two-part powdered stuff or the Prestone 7-hour flush - follow the instructions exactly!) and refill with coolant/water mix. DO NOT USE TAP WATER (If I only had a nickel...) Use distilled (preferred) or reverse osmosis-filtered (perfectly acceptable, and more common) water only.

Check your fan clutch as well - in the XJ (particularly RENIX years,) they seem to have a useful service life of 5-6 years. If you replace it, use a Sharpie pen to write the date you install it on the thing - it's just a good habit.

You can source a new "football" tank and cap from Morris 4x4 Center for a reasonable price.

lqguitarguy@hotmail.com

mine did the same, try reading my post 1990 overheating please help. has all kinds of things i did and im not even half way done i dont think. Also for our guy about the aluminum tank... really? its only 34 bucks at autozone. and it fits perfect. you need to get the tank with the bottom nipple and the top for the overflow. my advice. spend the 2 t0 3 hundred bucks on new stuff. cuz chances are if it doesnt look new then it probably isnt, and its worth the money to have everything working in sync and have everything last for a while, then to only replace one thing to have 2 others go out.

redrunner

Convert it to an open system is the best way to fix that over heating problem. You can pick up a after market fill neck that fits in the upper hose and converts the rotten closed system to an open system. I have put these in both of the 89s I have and that ends the over heating. Total cost was less than the one new plastic I got that cracked within one year.

Jakenfire

I had an overheating problem with my 87. I found that the nipple on the top of the reservoir was corroded and clogged. I just replaced the reservoir and haven't had a problem.

Bustedknuckle

LMFAO! Guess what I have? It's a 1990 XJ, and guess what it's doing?

I've been reading though the 167,243,476 threads on Renix XJ's overheating, and I choose to reply to this thread seeing as how the symptoms seem as close to mine as I could find.

Like OP said, start her up, within a few minutes she'll sit in the red. New Thermostat went in, new thermostat housing. Fan clutch is fine, electric fan is hard wired to a switch, rest of the system is fine, not a head gasket. Plastic bottle is intact with a new cap as well.

I've ran the system for a few to burp it, and it went decent, didn't see a drop in temp though. As soon as I shut down, it started blowing off coolant like crazy. I re-filled. This time, instead of getting air pockets, it'd puke coolant out in spurts.

Not looking for a "ZOMGOGGLES HELPS ME WITH TH3 HAX", just curious why dropping the nose and rasing the rear seems to work better, I understand for the sensor, but is there an added benefit of better flow that way?

Also, any more info on this "aftermarket filler neck" to convert. Have been looking around, can't seem to locate this one.

freegdr

i have bought 3 bottles in the time i have owned my 89 up date to the system on 94 xj no more ****ty bottle bennet auto rad 125 bucks over flow tank 20 bucks done

freegdr

finished look just chang cooling fan switch usin old rubber gasket on switch and one on plug in new rad and change top and bottom mounting brackets from old radiator to new old brackets are one quater inch shortet than new ones run hose to over flow bottle from nipple by rad capm your done

T-Paules

Didnt want to start a new thread but I have an odd problem. I just got a csf triple core all metal rad, triple efan kit from dirtbound, derale high amp dual fan controller and hooked it all up the past two days. All of the wiring and mechanics are installed properly and the fans work the way they're supposed to. I previosly was running a taurus fan and stock rad and it never went above 212. Now it is overheating at idle. When i give it throttle my gauge instantly goes down.. i just replaced the temp gauge sensor so thats working properly. I just built and installed this engine last year and did alot of work to it by myself. I know just about everything there is to know about it. The mechanics at my uncles shop call me when they have problems with jeeps there. Lol. But anyway the only thing i could think of is the tstat not working right. Im gonna check it but just wanted to see if anyone else has any clue what it could be but it obviously is a restriction problem. Could the water pump just die that quick? Idk but this is my DD and i gotta figure something out. Its a 93 xj 4.0, base model, 8" IRO long arm, ford 8.8 posi soon to have ad44 when i finish it