2001 Dodge Dakota

is the coolant level at proper height both in radiator or overflow tank? If so check your radiator cap it may not be holding pressure or drive belt could be faulty or not adjusted properly, Also radiator core could be cloged or radiator grille dirty and restricted

Also, check for crumbling fins between the cooling tubes. When this happened on my '88 Grand Caravan, it would run warm at anything over 60 degrees outside and 60 miles per hour. Normally, cooling gets better at highway speeds due to increased air flow, but air flow is irrelevant when the fins are gone. The extra heat generated at higher speeds can't dissipate to the air fast enough so the temperature goes up.

In my case, running the front and rear heaters brought the temperature down very quickly. The next year, it ran warm while cruising across Nebraska at night and 30 degrees outside. New radiator solved it. For the last six years, I dragged an enclosed trailer that's bigger than my van to an old car show swap meet. Can barely hit 65 miles per hour due to excessive wind resistance, but the temperature stays right where it should be.

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