Heater Hoses Installed Incorrectly
This bulletin involves inspecting the heater hoses and possibly draining the engine coolant, swapping the heater hoses and refilling the engine coolant.
Some vehicles may have been built with one or more of the following:Heater hoses installed in reversed order. If the coolant was drained and replaced, a sign the heater hoses are reversed is the vehicle will also make a gurgling noise.