Edmunds Answers

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  • avatar 0patience 11/05/11 3:18 am PST

    Mor than likely, you have a coolant flow problem in the cooling system. Whether it is a blockage in the radiator, coolant hoses or heater core is difficult to say.
    When was the last time the cooling system was changed out, cleaned or other wise?

    My first course of action would be to pressure test the cooling system and radiator cap. If the cap is bad, replace and road test.

Answers

  • 0patience 11/05/11 3:18 am PST

    Mor than likely, you have a coolant flow problem in the cooling system. Whether it is a blockage in the radiator, coolant hoses or heater core is difficult to say.
    When was the last time the cooling system was changed out, cleaned or other wise?

    My first course of action would be to pressure test the cooling system and radiator cap. If the cap is bad, replace and road test.

  • cl1997cummins 11/05/11 3:10 pm PST

    I have only had the truck 7 months so I do not know if the dealer did this or not. I will try a new radiator cap first then have it pressure tested. Thank you for the idea.

  • 0patience 11/05/11 8:45 pm PST

    Oh man, I should have thought of this first.
    I got to thinking about this problem and something was gnawing at me about it and I went back and re-read your original post carefully.
    Do me a favor and check the fan hub. With the engine off (of course, but I had to say it), grab the fan and see if the fan blades will rock from side to side. You may notice the hub is loose. If it seems ok, then spin the fan fairly vigorously and then when you stop spinning it, it should stop failry quickly. If the hub is loose or the fan continues to spin, it is likely that the fanhub is not working properly.

    The problem with the Dodges is that the fan hubs tend to wear out prematurely and when they do, they will sometimes work fair when going down the road, more because of air movement from the vehicle than the fan working. And at an idle, the fan may or may not work.
    The last check is to find the spring on the inside of the hub, with a pair of pliers, unhook it and run the vehicle as before and see if the symptoms go away. If they do, the thermal spring is bad and will require replacment of the hub.
    Let us know what you find.

  • thecardoc3 11/06/11 12:24 pm PST

    Some things we need to see first hand in order to be sure about the facts. I'd like to drive this with a scan tool hooked up to monitor the engine temperature that way instead of just watching the gage. That being said, it's not all that incommon to have an air pocket blocking coolant flow through the heater core, so bleeding it may be required. At the same time, if the core itself is becoming restricted, a noticeable difference in the temperatures of the hoses would be observed by touching them with the heater on full and the engine running. Essentially they should both "feel" too hot to touch.

    From there you get into a possible coolant concentration issue. too much coolant actually does not pick up heat correctly and the engine could in fact be overheating even though the gage is staying low. Make sure the concentration is bewteen 50/50 and 65/35 coolant to water. More than 65% coolant again can cause it to not properly pick-up and then transfer heat to the radiator as well as the heater core.

    Now unless these are working fairly hard, they don't get hot very quickly so you must be precise with your evalution of what is correct as compared to what is not. A low coolant level and air pockets should be high on you list to rule out. In the shop we can control that possibility by pulling the system into a vacuum and filling it from there.

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