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Q: Antifreeze leak in a 1999 Dodge Ram 1500

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The window is fogging up with antifreeze. I think it's the heater core.

Having a coolant leak inside the cab of a vehicle pretty much means that the heater core has developed a leak. Usually when the coolant fogs up the window, the way it does with your Dodge Ram, it is an indication of a pinhole leak (a very tiny hole) where the coolant instantly boils into a vapor and travels up the dashboard onto your window. If the floorboards under the dash are damp or wet then that would indicate that the leak is more serious.

Replacing the heater core is a labor intensive job and requires the technician to remove the dashboard completely, as well as remove all of the refrigerant from the A/C system. This is due to the heater core and A/C’s evaporator being located next to each other and removal of the evaporator being necessary to replace the heater core. As you can see a serious job like this is best left to a professional and enlisting the assistance of a certified mechanic, such as one from YourMechanic, to diagnose your coolant leak will ensure this repair is done quickly and safely.

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