[theman440]

Recently I'm smelling coolant inside the cab, there are no leaks that I can find - is my truck telling me it's to replace the heater core?

 

[DadzDodge]

Maybe, but not necessarily. We have a '96 Ram that was only driven 1,000 miles in 15 months before my father-in-law gave it to my teenage son, and it had a lot of cooling system problems due to neglect. The water pump and thermostat needed changing right away, and once cold weather arrived I found that the heater core was nearly plugged and also needed replacement. Even after I had changed all that, we're STILL getting a whiff of coolant smell sometimes. While trying to figure that out, and also wondering why I'm having to add coolant periodically, I took a look under the truck and sure enough, I found a small bead of coolant on the bottom of the fan shroud. I suspect a small leak in the radiator. If you can let the truck sit for a while and then have a look under the radiator, and all around the lower side of the fan shroud, you MIGHT find evidence of a leak there.

Thinking about the water pump for a moment, do you see any evidence of coolant being thrown to either side of the engine bay? Before we replaced our water pump, we seldom found a puddle under the truck (below the water pump), but there was very obvious evidence of coolant being thrown to either side of the engine bay. You might look for stains on either or both wheel wells, aligned with the location of the water pump.

I know a lot of guys report leaks from their heater core, but that wasn't the case with us. Our core was just plugged up and wouldn't have led to any smell in the cabin.

After changing the water pump, thermostat and heater core, the thought of replacing the radiator seems like a breeze. If you do end up having to replace anything, the radiator might be the easiest.