When the fans blow
Q
Why do the fans come on so often on my MacBook Pro 15-inch 2018? I’ve installed third-party temperature monitoring and fan control software, but that hasn’t helped much. Could it have a defective logic board?
A
Each Mac has several temperature sensors within its case, monitoring key sites such the processor, its chipset and storage. Readings from those, and estimates of current processor workload, are checked constantly by a sub-system in macOS called Core Duet, which controls cooling mechanisms including any fans. At the heart of these is the Mac’s System Management Controller (SMC). If this temperature management goes wrong – when the air vents in the case are blocked with dust, a sensor is defective, or the SMC is failing – the danger is that its logic board will overheat, cause damage to components like the processor and internal storage, and require replacement.
First, uninstall the third-party software which could be the cause rather than any solution, clean any air vents, and reset its SMC according Apple’s instructions at apple. co/3RDIO2g.
The fans should still come on to increase cooling when processor load or ambient temperature rise, but if they come on at other times, such as when it’s idle in a cool, well-ventilated location, then it’s probably best to get it checked over by an authorised Apple service provider.