Cooling help

Hey guys, I have tried searching and I haven't had very good luck, so here goes...

I have had cooling issues with my Jeep for a long time. I have 2 electric fans, no mechanical. New water pump and thermostat. My Jeep overheats after a while on the trails and none of this has fixed the issue. I thought I had it when I found the water pump leaking, but no such luck. The last time I overheated I cracked a tank on the OEM radiator. I am going to replace the radiator (obviosly), but I have a few questions.

Is there some kind of chemical I can flush through the water jackets to be remove scale and rust, etc from the block and head that will be worth using?

Also, I have heard of guys converting the cooling system over to an open type system. What are the benefits of doing this?


A little about the Heep:
1988 XJ, never sees the street and never will again.
I plan to remove the AC condenser
I have two 10" ( iirc) electric fans-will build a shroud when I get the new rad.
new water pump
new thermostat
I am also considering remote oil and trans coolers (not sure where to mount them)
I have also considered installing louvers in the hood, but I donr want to go cutting on it if it isn't going to make quite a difference.

Any help would be appreciated...

Best case scenario, put vents in the hood, do the aux coolers, 3 core radiator, shroud for the fans, thorough system flush with prestone heavy duty flush, change to open system, and make sure it is properly burped.

I was going through these problems for a while too. First thing I figured out was that the cheap thermostat I installed from Autozone was sticking and the heep wouldn't overheat until about an hour into my drive. Replaced that with a quality T-stat from Napa after flushing the whole system with 2 bottles of that prestone cooling system flush also sold at Napa. I poured one bottle in the heater core via the heater hoses and another bottle into the upper radiator hose. After following all the instructiuons on the label. I forgot to mention that before adding the flush to the system I unhooked both of the heater hoses from the engine and ran my garden hose on full blast through them to knock any big chunks out of the heater core. I probably flushed a sandwich bag sized amount of crap out of just the heater core alone. after running it with the flush, burping the system and buttoning everything up I havent had any problems and my heater blows hotter than ever. I am pretty sure that my cooling system was clogged full of that bars stop leak stuff but I will say that the prestone flush has usually worked great for me. Reverse flushing everything with the water hose helps alot too. good luck and post up what you try.


P.S. The brand of T-stat I originally used was a Motorad and apparently the are considered fail safe t-stats and from what I read the like to stick in the open position, which believe it or not can cause overheating too.

I converted my wifes 89 to an open system. Best money I ever spent on a Jeep!! Added a pair of Gen-Right vents to the hood of my 94 and the gage reads 5-10 degrees lower and my beer doesn't boil when I sit it on the hood.

Why not go back to the mechanical fan? It moves more air than the electric
What gears/tires are you running? My overheating issues went away when I went from 3.07's to 4.10's on 33" tires

I'm a lazy old guy, took mine to a shop an had them Flush and Clean the system out.1989 closed unit with AC running offroading during the summer in Palm Springs CA and it is running 215 in the canyons.I think thats HOT but everybody says thats perfect.I do this this every 4/5 years and never think about over heating anymore.Matter fact, time is coming to do mine again this year before summer hits.

Just two 10" fans? What kind of CFM do they pull?

hubs97xj said:

Just two 10" fans? What kind of CFM do they pull?

Click to expand...

It's been my experience that you get what you pay for with fans. I tried many brands of fans and was never happy until I spent the money on Spal fans. They pull a crapload of air.

what about DirtBound electric fans with their shroud - is it worth a try?

I used to always overheat on the trail.

I added hood vents, a tranny cooler (bypassed the radiator altogether), replaced old crappy radiator and flushed out the system with the Prestone stuff. It runs nice and cool since then.