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Unread 07-11-2013, 07:21 PM   #1
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04 4.0 bleeding coolant

04 4.0 with 140k miles

Was under the jeep tonight changing out an o2 sensor (turns out I need a pigtail as a wire is broken right next to the connector on the harness side :banghead: ) when I noticed a few red drops on the front edge of the oil pan . Can't see the water pump weep hole, but noticed some red crusty stuff growing out the side of the thermostat housing...

How common is it for the housing to leak on these?

I'm prob going to replace the pump anyway, and do a flush (even though I hate taking off good parts) any recommendations for brands of punp that are good, or to stay away from?

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Unread 07-15-2013, 06:38 AM   #2
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red? sure it isn't tranny fluid? your tranny cooler lines go by there.
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Unread 07-15-2013, 06:48 AM   #3
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The water pump weep hole is on the underside of the pump housing, pretty close to the shaft. I could not see mine, until I removed the water pump.

The red you see could also be HOAT coolant, which is generally red in color. That is the spec-ed coolant for the '04. When I replaced my water pump, I also replaced the thermostat, the thermostat housing and gasket. Since I hate draining the system and spending money on coolant, I figured I would do it all at the same time. Actually, I also replaced the two radiator hoses and heater hoses while I was at it. And, the hard pipe that screws into the water pump.
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Unread 07-15-2013, 10:36 AM   #4
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X2. I did the same to mine.
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Unread 07-15-2013, 10:37 AM   #5
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Unread 07-15-2013, 04:53 PM   #6
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its definitely coolant. I was surprised to see it growing a red crystal out the side of the thermostat housing though.
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