Reinstalling OS to fix fans?

[rsherid]

Would reinstalling OS X fix the fans that come on as soon as I boot up my MacBook (Late 2013)?

 

[Raz0rEdge]

Reset the NVRAM/PRAM which is more likely affect the fans than reinstalled macOS.

 

[chscag]

Reinstalling macOS can not fix a hardware problem. If the fans are coming on as soon as you boot, there may be a hardware problem with your MBP. You should resolve that first.

 

[rsherid]

Reset the NVRAM/PRAM which is more likely affect the fans than reinstalled macOS.

Done that and cleaned a little dust out of the fans. Anything else?

 

[chscag]

Done that and cleaned a little dust out of the fans. Anything else?

Run the Apple Hardware Test to see if it comes up with anything.

 

[Raz0rEdge]

How fast do they come on when you power on the Mac? Has it always been that way? When did it change?

 

[rsherid]

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Run the Apple Hardware Test to see if it comes up with anything.

No issues detected.

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How fast do they come on when you power on the Mac? Has it always been that way? When did it change?

Almost immediately. Since day one this Mac was started with an old Time Machine backup and I thought a fresh OS install would clear out any corrupt files, etc.

 

[chscag]

I doubt there's a problem with the GPU on that model since it's integrated with the CPU. Could be a bad temperature sensor causing the fans to rev up or even a bad thermal paste job from the factory.

iFixit: The Free Repair Manual may have some more information.

 

[ferrarr]

How about safe mode, Use safe mode to isolate issues with your Mac - Apple Support

 

[jpdemers]

You could install Macs Fan Control (freebie dowload) and see if it can override whatever is causing the problem.
I had the same issue when I replaced the internal HDD in an iMac with an SSD - the Mac got bad (or no) temperature data. Macs Fan Control solved it.

 

[chscag]

I had the same issue when I replaced the internal HDD in an iMac with an SSD - the Mac got bad (or no) temperature data. Macs Fan Control solved it.

That's one way. The best way is to purchase the drive temp sensor bypass cable from Apple Mac Upgrades - RAM, SSD Flash, External Drives and More. But Macs Fan Control is less expensive.