The Jeep Wrangler I purchased needed some preventive maintenance. The coolant in the recovery bottle looked dirty, and there were no records of it being changed. I also noticed that the heater didn’t get that hot. Good maintenance is especially important on an off-road vehicle so it seemed like a good time to get the caught up.
I started by draining the coolant out through the drain valve at the bottom of the radiator. Next, I drained the coolant recovery bottle. Once the coolant stopped dripping into the drain pan, I filled the system with distilled water, ran it and drained that as well.
Research indicates that its common for the Jeep Wrangler heater core to get plugged up, so I gently flushed it both directions with compressed air and distilled water. A lot of crud came out.
Finally, I refilled the cooling system with a 50:50 mix of Zerex G05 coolant using a Lisle Spill Free Funnel. The funnel raises the level of coolant above the radiator, this aids in getting the air out of the system. A note on the Zerex G05, it is almost clear and has a lot less color than factory. I replaced the radiator cap with a Gates# 31525 (which was Motorad brand in a Gates box).
Zerex G05 is the specified coolant for the JK Wranglers with the 3.8 only. If you have a 3.6 DO NOT USE this coolant.
- Radiator Cap - Gates# 31525
- Coolant - Zerex G05
The cooling system took roughly 3 gallons of coolant.
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