2003 F350 7.3L Unusual Overheating Problem

Just looking for ideas, but basically, when I drive around town, including the highway, the needle stays in the same spot. However, if I pull over, put it in park, and rev it a little, it will go down rather quickly. Once I get on the highway and stay there for about 20 minutes, the needle starts to creep up. I don’t have any coolant leak, and the truck doesn’t appear to be experiencing any power issues. There’s nothing leaving the tail pipe. Only 125k remain on the truck. I am seeking inspiration and things to make sure of before beginning to pull pieces. Thank you.

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Perhaps the water pump impellers are corroded and not circulating coolant effectively?

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Regarding the typical debris, there are no dents or damage to any part of the radiator. I am not sure if it’s the original one or not.

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It is advisable to check the area between the radiator and AC condenser first as it is often clogged with leaves and dirt.

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Thanks for the suggestions, I will definitely try that on my next day off. I really appreciate it.

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Could it be the thermostat housing? I had a similar issue where the truck wouldn’t heat up enough for the thermostat to open when driving around town, but once at highway speeds and the coolant started circulating through the thermostat, the temperature would rise. Mine definitely had a coolant leak. Maybe air in the system is getting excessively hot once the engine reaches operating temperature?

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I considered that as well, but the housing is metal, not plastic like the one on my old Jeep Wrangler.

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Really wranglers have plastic housing’s?

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Indeed. The housing and thermostat are purchased jointly. Replacing merely the thermostat is not possible. :100: