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Coolant Flush - 2006 Jeep Wrangler
4.0L - 6-cyl. engine

The factory service manual shows the engine coolant drain plug on the left rear of the engine block, but I wasn't able to find it. I think it's buried somewhere under the exhaust manifold.

I purchased a Prestone Flush 'N Fill Kit and installed the "T" on the heater inlet hose as the Prestone directions show. The heater inlet hose on a Jeep Wrangler is the top heater hose that runs from the firewall to the top of the engine. I installed the "T" just a few inches behind the plastic clip that holds the heater hose to the top of the engine.


Follow the directions on the Prestone Flush 'N Fill package. I had a problem connecting the yellow Splash Deflector Tube to the radiator fill-hole. The lip on the Deflector Tube was slightly too large to snap into the radiator-fill opening. Rather than force it into the opening, and possibly break something, I just filed down the plastic lip on the Deflector Tube. After a little filing, it snapped right in. I flushed the cooling system, then disconnected the lower radiator hose at the radiator to drain the system as much as possible.

After flushing and draining, re-fill with a 50/50* mix of Zerex G-05 Antifreeze or Mopar Antifreeze and distilled water. Zerex G-05 and Mopar are the ONLY brands that Jeep recommends for late model vehicles.


Be sure to check your owner's manual for your cooling system capacity. Add the proper amount of antifreeze first, then top-off with distilled water. The Prestone directions say to fill through the Prestone "T," but I filled mine through the radiator fill-hole. Disconnect the white plastic overflow bottle and flush it out. Re-fill with a 50/50 mix of antifreeze and distilled water. Fill just to the "cold" line on the bottle.

Run the engine for 10 minutes or so to warm it up and let it "burp" out any air bubbles with the radiator cap off. Add more distilled water as necessary.


*Read the chart on the back of the antifreeze jug. For proper freeze/boil protection you must have at least a 50/50 mix of antifreeze/distilled water, but not more than a 70/30 mix. If you mix more than 70% antifreeze, the freeze protection actually worsens and you could have a freeze-up in the winter.