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DIY convert from closed to open cooling. This Write up is how I converted from closed to open cooling. You may choose other parts to achieve the same end result. I am converting because I am tired of messing with the pressure bottle, to remove the heater flow valve, and replace old hoses. Parts: Radiator with filler neck $82.57 * Part number: CU1193 Radiator cap $24.99 * (I bought a fancy cap with built in thermometer.) Part number: 2471S 2 Gallons antifreeze coolant $14.99 ea ($24.98 for 2) *** Item number: 7020022 10' 5/16 hose $19.90 *** $1.99 per foot Item number: 5194083 4' 3/4 heater hose $5.56 *** $1.39 per foot item number: 5192978 4' 5/8 heater hose $5.56 *** $1.39 per foot Item number: 5192951 Two 3/4 to 5/8 hose adaptors $2.99 ea ($5.98 for 2)*** Part number: 80424 A junkyard radiator bottle (I think mine was from a ZJ or WJ dad snagged it for me) Total conversion cost: $169.54 + S&H and tax Optional Parts: Later model thermostat housing with temperature switch new water pump Dual Fan Controller Second Electric fan for dual conversion Wire Relay or Fan Controller Power Switch MJ or XJ 2.5L Radiator Bottle $16.99 ** Part number: 52003213 MJ or XJ Bottle Cap $7.97 ** Part number: J3223202 Ordered from: Amazon.com * Morris4x4.com ** Advanced Auto Parts *** Tools: Gloves Safety glasses Knife or box cutter Phillips and flat head screwdrivers Bucket T-25 T-30 8mm Socket and or wrench 10mm Socket and or wrench Getting Started Start by draining out the old radiator fluid, removing the upper and lower radiator hoses, fan temperature switch, and if you have an auto transmission the transmission cooler lines from the radiator. Use an 8mm socket or wrench to remove the electric fan and clutch fan shroud. The radiator support is held on by several bolts 10mm and T-25 or T-30 (sorry mine where all stripped before I started not exactly sure the actual size). The bolts removed connect the support to the frame and front clip, then they are all out remove the radiator support. The radiator should come out without much fuss. With the radiator out of the way now would be the perfect time to convert to Dual electric fans and replace the water pump. Sadly I was running out of time due to fighting with stripped bolts so i was not able to do ether.... Depending on the radiator you get you may not need to change the thermostat housing. My thermostat housing is from a later model XJ, and can use a temperature switch. However the radiator I purchased has the hole for the fan temperature switch. Remove the 3/4 hose and the 5/8 hose from the thermostat housing and the water pump. Remove the old coolant pressure bottle and the hoses going to the heater core. Cutting the hose may be needed. The new hoses will need to be adapted from 3/4 to 5/8, the reason for this is the thermostat housing outlet is 3/4 connecting to the heater core that is 5/8, and the heater core outlet is 3/4 connecting to the water pump inlet that is 5/8. After all the old hoses are removed take your new 3/4 and 5/8 hose and route it however you like, then measure where to cut the hose in half. Use the 3/4 to 5/8 adapters as needed. Again the hose routing is: 3/4 from thermostat housing 3/4 to 5/8 adapter 5/8 to heater core inlet 3/4 from heater core outlet 3/4 to 5/8 adapter 5/8 to water pump The new coolant bottle is the next challenge. I ordered a 2.5L MJ/XJ coolant bottle that should fit on the drivers side fender, I will likely need to go back to a cone air filter to make room for it. Till I decide for sure what bottle I am sticking with I used one from a Junk yard Jeep and slightly modified it to work. I had to remove the old pressure bottle "shelf" to make room. I used a self tapping screw to attach the radiator bottle to the back of the engine bay where the old bottle was located. I routed the 5/16 hose around the back of the bottle and used the heater hoses as a bridge, ending where the radiator filler neck will be. Install the new radiator and reconnect the upper and lower radiator hoses. Reattach the radiator support. Connect the Coolant bottle hose to the filler neck. For good measure I zip tied all the new hoses in place. Fill the radiator system with 12 quarts (3 Gallons) of coolant. Must be a 50/50 mix, you can use pre-mix or concentrate with distilled water. you may not be able to fit all 12 quarts as there will likely be some coolant still in the engine. Bleed the air out of the system, Renix engines have a coolant temperature sensor on the back of the head accessible from the engine compartment. Clean up and all done Prior to this conversion My Jeep would boil over in 20 minuets and interstate travel was a no go. Now the temperature has yet to pass the 210 mark while traveling 75 mph on the interstate. A side note, my A/C seems to be blowing cooler as well now....