Figure 1

Originally Published in Issue 29 of 4Low Magazine

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By Christian Sturtz, [email protected]

Photos by Christian Sturtz

One of the most overlooked and neglected systems on vehicles is the cooling system. The cooling system affects many different systems of the vehicle, including:  engine performance, vehicle emissions, transmission, and the a/c system. There are several components that make up a cooling system, including: the object you are trying to cool (engine), water pump, thermostat, temperature sensor, hoses, radiator, fan, shroud, overflow/recovery tank, coolant, etc.

The water pump circulates the coolant through the cooling system, while the thermostat helps to regulate the operating temperature of the engine. The thermostat also helps with vehicle emissions and allows the vehicle to get warm enough to produce heat for passengers. Temperature sensors let the driver and computer know what is going on and they can be used in controlling electric fans. Hoses connect components in the cooling system while the radiator gives the coolant a large surface area for heat transfer. The fan pulls air through the radiator and helps with the heat transfer as well. The fan shroud directs and funnels air from the fan through the radiator. Meanwhile, the overflow/recovery tank allows expansion and contraction of coolant in the system. Coolant is a 50/50 mix of water and antifreeze. Antifreeze is mostly glycol based (though that is changing), which helps keep the water from freezing; it also has a lubrication and anti-rusting agent in it. Lastly, other components can be included in coolant systems, such as a heater core.

Figure 1
In this article we are going to cover cooling system upgrades and related maintenance on a 2005 Jeep Wrangler LJ. The upgrades will include the radiator, electric fan kit, and silicone hose kit by Mishimoto. We will also install a Flow Kooler high performance water pump. At the same time we chose to replace some related parts, including: the temperature sensor, belt, idler pulley, tensioner assembly, and thermostat.
Figure 2
We started by unhooking the battery and draining the coolant into a large catch pan, that was left under the Jeep until the reassembly stage. These large black plastic pans work great and can be found at most home improvement stores. The coolant can be drained by unscrewing the petcock, found typically on one of the lower corners of the radiator. The upper hose were removed next, along with the overflow/recovery tank.
Figure 3
Next, the fan was removed by sliding it up and out of the shroud. This fan screws onto the front hub of the water pump and has standard threads- right tight, left loose. The easiest way to remove the fan is with an air hammer and tool. Most auto parts stores have a rental tool program and rent out tools that can be used to remove the fan. The shroud was unbolted from the radiator and removed. Then, the lower radiator hose was removed along with the transmission lines from the lower part of the radiator. These lines are removed easiest with a specialty Jiffy-Tite tool, which can often be rented too. Another option is to remove the E-clip with a pick and the line will slide right out.
Figure 4
The radiator was unbolted and removed next. Then the belt, tensioner, idler, and water pump pulley were removed.
Figure 5
We unhooked the heater hoses from the thermostat housing and steel pipe off of the water pump. The steel pipe’s orientation was marked and the water pump removed. Finally, the temperature sensor was unplugged and removed.
Figure 6
We thought it was a great time to install the additional temperature probe for the electric fan kit. We found a couple brass fittings at a local parts store that allowed us to neatly and cleanly install the factory sensor and additional temperature probe. Next the thermostat housing was removed and the mounting surface for the thermostat and water pump were cleaned.

Figure 7Now the reassembly begins! The Flow Kooler water pump’s design is different to increase performance. You can see by the pictures their design differences. The steel tube must be removed from the original pump and reinstalled on the new pump. Make sure to test fit the pump for tube position before trying to bolt it into place. It is always a good idea to use thread sealant on the steel tube threads as well as the water pump/thermostat housing bolts. Then clean up the thermostat housing, install the thermostat, and heater hoses.


Figure 8 

The water pump pulley, new tensioner, idler, and belt were installed. It’s a good idea to place thread lock compound to the pulley bolts. The radiator was then bolted into place and the lower hose was installed

Figure 9
Next the electric fan and overflow/recovery tank bracket were bolted into place. The upper hose was installed along with the overflow/recovery tank.
Figure 10
To finish it up, the wiring for the electric fan was completed. The transmission cooler hoses were hooked back up with the help of a couple real short pieces of 3/8” transmission cooler hose and a few clamps. The radiator comes with 3 different style fittings to hook up the transmission cooler, use the ones that best fit your application. Complete wiring instructions available for the controller on Mishimoto’s website.

Finally, the vehicle is filled with coolant and bled properly. Now you have a vehicle that will run much better because you took time out to cool it off.


Mishimoto Automotive                                 Flow Kooler

18 Boulden Circle, Suite 14                          500 Linne Road, Unit 1

New Castle, DE 19720                                  Paso Robles, CA 93446

  1. 466.4744 805.239.2501

www.mishimoto.com                                    www.flowkoolerwaterpumps.com


Napa Auto Parts                                            AutoZone

800.538.6272                                               800.288.6966

www.napaonline.com                                    www.autozone.com


Parts Used:

Radiator (MMRAD-WRA-87)
Fan/Controller (MMFS-WRA-87NPT)
Hose Kit (MMHOSE-WR6-97BK)

Flow Kooler:
Water Pump (1750)

Temperature Sensor (TS3005)
Belt (K060882)
Idler Pulley (38043)
Tensioner Assembly (38163)

Auto Zone:
Thermostat (15359DLG)

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