Jeep Commando

Ive searched quite a few pages already on this topic, going from a Renix open system to a newer closed system, or whichever way. Ive read so much crap about it that Im all confused and cant seem to find any real threads/posts about it. It seems to me everyone just cheaps out and buys junkyard coolant bottles ect and retrofit them. Id like to swap everything, radiator, hoses, overflow tank, thermostat housing?, waterpump? Not sure on the last two, but regardless, Im going to put an entire all new cooling system in my 90' 4.0 Cherokee and would like to have a "regular" cooling system. Ive replaced that damned pressure bottle and cap about 4 times now. I currently have a leaking freeze plug and no thermostat which will be replaced as well. So, if someone could maybe tell me what year Cherokee 4L/AW4 would be ideal to take parts from, maybe I can get underway with this project and submit a write up about it. Thanks. Oh also, an upgraded radiator would be ideal, 3 row?

freegdr

its pretty straight forward , your gonna needto replace the frreeze plug ,because after you upgrade system your gonna start building up pressue its gonna leak worse .i did mine a while back heres what i wrote no need to change any sensors but the one in the radiator from old rad to new i used the rubber gasdkets from both rads on mine to make it easier to snug up .mines stick shift so check for tranny line working from old to new...https://www.cherokeeforum.com/f2/ren...d-shift-63044/

highmileage

you don't have to swap all that stuff alot of it is the same. when going to the new chrysler radiator change;
thermostat housing ( you will have to rewire for your temp sensor since it will be on the housing and not the radiator)
you can use your existing pressure bottle for a reservoir; take the pressure seal out of the cap, plug the stem at the top of the bottle by the cap, cross a hose over to fit the radiator suction and the neck on the bottom of the bottle,run the hose over the top of the bottle before running it to the radiator so that its in a suck rather than gravity.
Only problem I ran into was the temp sensor. The chrysler one seems to run on the low side. Tried replacing it with aftermarket but all they seemed to do was cause an overheating issue.
It's a very clean looking swap even the shop guys at dodge were very impressed. The overflow tank from another jeep wont work parts are in the way. Got the parts for mine out of a 93.

freegdr

he wants new stuff same as me dont need to add the sensor when the old one screw right into new radiator

mud-dog27

yea i never had to rewire anything.

my parts list.

> 91+ rad, i used the 3 core
> upper lower rad hoses
> some hose for the overflow
> universal overflow bottle

i believe you can even get away with using the ****ty old renix rad and just using an inline rad cap spliced into one of the hoses but thats kinda ghetto.

and either way the leaky frost plugs will need changing.

Jeep Commando

Sounds good, does the overflow bottle have to be mounted higher than the radiator ect?

CPTslackass

My fix. A first gen Dodge Intrepid Pressure bottle. After doing a cooling system overhaul, I installed the new Pressure bottle, with the new radiator, water pump, thermostat and various hoses. I have never had a problem with the system. Works great!

mud-dog27

not sure if it needs to be higher, i just mounted it on the passenger side firewall where the pressure bottle was

highmileage

dude, sorry the 93 radiator doesn't have a boss for the temp/fan switch sensor. maybe the 91 does haven't seen one. And as for the new stuff up to like 96 or later 4.0s' all the parts are the same fit as the renix, all I was suggesting was that if his stuff was working why replace it.

Jeep Commando

Tired of replacing the expansion bottle or whatever its called. The cap keeps blowing off anytime I get close to operating temp and the coolant boils. Ive filled/bled the system numerous times, I replaced that freeze plug. Nothing else seems to be wrong really.

sam24th

If you get a brand new radiator for a 91+ HO engine the radiator will have the coolant temp sensor needed. They all have the plug for the coolant temp sensor from the part numbers I looked at. If you want to retain your renix radiator, you can get an inline cap from a dodge dakota. Basically replaces your hose and puts an inline rad cap.

Option one:
-91+ HO radiator
-over flow bottle
-upper and lower rad hoses
-hose for overflow bottle

Option two:
-dakota rad hose
-overflow bottle
-hose for overflow bottle