Continuing from page 1, we are flushing the cooling system in the jeepfan.com 2004 TJ Unlimited. In addition we are replacing the radiator cap and thermostat.
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Thermostat Installation
Remove the upper radiator hose and the end of the heater hose that connects to the thermostat housing. Unplug the temperature sensor. Remove the 2 bolts on the housing. The thermostat is located within the housing and will come out easily with the housing removed.
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Clean the gasket surface on the engine and the housing, be careful not to gouge the surfaces. Apply some RTV to the engine and housing surfaces. Insert the new thermostat into the engine and use the two bolts to hold the gasket to the housing. Place the housing back on the engine and tighten the bolts.
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old thermostat |
cleaning the gasket area |
new thermostat |
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new thermostat installed |
sealer and gasket prep |
housing reinstalled |
At this point replace the hoses and tighten them down. We like to replace the factory hose clamps with new band style ones since they don’t require a struggle to install/remove. Make sure the drain is closed. We chose to install a flush kit which installs a fitting into the heater hose that allows a hose to be connected to aid in flushing the system. This fitting is also useful for bleeding air from the system.
Flushing
It’s best to flush a system in multiple stages. We picked up a bottle of Prestone radiator flush and cleaner and followed the directions on the bottle. This process involved dumping in the flush and filling the system with water.
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The engine is run for a bit of time to allow the flush to circulate through the entire cooling system. Some owners will run the Jeep for a few days with the flush in it. After allowing the engine to cool drain the entire system and refill with plain water. Run the Jeep again and allow it to cool. Fully drain the system and use the flush tee that was installed to fully rinse the system. During this time it’s a good idea to check for leaks within the system while there is just plain water within.
Antifreeze
At this point the system should be clean and ready for new antifreeze. Most antifreeze requires dilution with water and most areas will use a 50/50 mix of antifreeze to water.
Water
We always purchase some bottles of distilled water to dilute the antifreeze over using tap water. Distilled water is pure water and contains no minerals which can contaminate the Jeep’s cooling system.
Wrapping it up
With the Jeep’s cooling system full of a new antifreeze mixture and no leaks the Jeep is ready for action. Properly dispose of the old antifreeze, search for antifreeze collection locations in your area. Some are free, some require a minimal payment.
