Which heater coil are you referring to? Also I’m in Houston as well and selling mine. It has 98k miles $3700.

The heater coil inside the windshield washer tank - its literally coil shaped and is filled with engine coolant, its regulated by the small square/rectangle shaped unit in between the lines. That thing is the thermostat for it and has O rings to seal it.

__________________
2012 BMW X5 (Beef + Granite suspension model)

1995 E300D - The original humming machine (consumed by Flood 2017)
2000 E320 - The evolution (consumed by flood 2017)