Rick's Free Auto Repair Advice

Repeat rear evaporator coil failures — GM

Avoid repeat rear evaporator coil failures — GM

GM has issued a service bulletin #16-NA-046 to address repeat rear evaporator core failures on the vehicles listed below. GM has identified the blower motor as the cause of repeated failures. Replacement of the evaporator core and the blower motor with an updated design will fix the problem.

What causes the repeat rear evaporator core failures on GM vehicles?

GM has determined that copper dust emitted from the rear blower motor brushes accumulates on the aluminum surface of the evaporator core fins where it combines with condensation. The combination of water, copper, and aluminum generates galvanic action which deteriorates the aluminum evaporator core tubes and fins, causing a refrigerant leak.

Fix for Repeat rear evaporator coil failures — GM

GM has redesigned the rear blow fan, changing it from an open to closed design. In the open design, the fan can suck copper particles from the motor and circulate the particles throughout the heater box. The closed design fan eliminates the suction from the motor.

gm blower fan

Old versus new style blower fan

Vehicles affected by service bulletin #16-NA-046

2013-16 Buick Enclave

2013-16 Chevrolet Traverse

2013-16 GMC Acadia

All vehicles built before October 6, 2015

Updated part numbers for evaporator and fan

Update blower motor # 23361388

Updated 23361388 fan and motor

Updated EVAPORATOR 20827668

evaporator core 20827668

Evaporator core 20827668





Posted on by Rick Muscoplat

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