Truck overheats when driving speed limit

2005 DODGE RAM
12,000 MILES • 4.7L • V8 • 2WD • AUTOMATIC
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CHARLESNOSEFF
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Runs at normal temperature while idling. But it overheats when driving speed limit. New: radiator, water pump, clutch fan, thermostat, coolant reservoir. After it heats up I can pull over and let it idle and it will cool back down. Motor was just installed. Had 120,000 miles on it. motor runs great. Please help.
Feb 9, 2020 at 11:01 AM
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SCGRANTURISMO
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Hello,

This sounds like it could be a problem with the tension on the drive belt for the water pump. Can you please check and ensure that the belt is not slipping and get back to us with what you find out.

Thanks,
Alex
2CarPros
Feb 9, 2020 at 11:52 AM
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CHARLESNOSEFF
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I'll check and get back to you. At a funeral now.
Feb 9, 2020 at 12:04 PM
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CHARLESNOSEFF
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Checked belt. The belt was routed wrong. Would have never seen it if not checking the tension. Thanks so much.
Feb 9, 2020 at 2:26 PM
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CHARLESNOSEFF
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Belt is installed correctly but still getting hot. What's puzzling is top of radiator gets hot but the bottom is still cool. Only thing I can guess is thermostat is not opening up all the way.
Feb 10, 2020 at 12:08 PM
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CHARLESNOSEFF
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Or maybe one of the hoses are sucking together and restricting the water flow at high speed.
Feb 10, 2020 at 12:11 PM
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SCGRANTURISMO
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Hello,

That sounds like a distinct possibility. Also I might add doing a cooling system flush and fill as well. Here is a link describing how to do it below:

https://www.2carpros.com/articles/coolant-flush-and-refill-all-cars

In the diagrams down below I have included the instructions for the removal and installation of your vehicle's thermostat. Please go through these guides and get back to us with how everything turns out.

Thanks,
Alex
2CarPros
Feb 10, 2020 at 9:31 PM
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CHARLESNOSEFF
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While my truck was in shop waiting for the new motor. my radiator, fan shroud, transmission cooler and power steering cooler was stolen. So they said. I got my truck out of shop and hired a mechanic to swap the motors out. It has all new cooling system with new coolant. This is after my truck sit in the shop for two years. Thinking about taking thermostat out and running it to see if it still gets hot. I sure thank y'all for helping me out with this problem.
Feb 11, 2020 at 10:57 AM
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CHARLESNOSEFF
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Forgot, I had put new water pump and thermostat in old motor before they told me it needed another motor. So it sit for two years without any coolant in it.. so thermostat was dry the whole time. Thanks
Feb 11, 2020 at 11:01 AM
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STRAILER
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Does the radiator have a shroud ? if not this is causing the problem also let's double check the belt routing because if you are turning the water pump backwards it will cause this as well. Check out the diagrams (below). Please let us know what happens.

Feb 14, 2020 at 10:34 AM