Fan momentarily races on cold startup

[JohnnyAllentow]

A cooling fan races momentarily 1-2 seconds on cold startup then settles down.  It does not race on restart or when the desktop is shut down for a short time.  When this happened, a BIOS blue screen would pop up, which could be cleared by hitting the Return key and would allow boot up to continue.  I checked the fans and cooling fins, and cleaned them.  According to HWMonitor, the fans are running properly according and all temperatures and voltages on the motherboard are normal.

I replaced the CMOS battery and reflashed the BIOS with the latest version from HP, which seems to have stopped the BIOS blue screen, but I can still hear the cooling fan race momentarily on cold startup.  I don't know if the new BIOS has permanently fixed the blue screen if it was caused by a timing issue on startup. 

 I'd like advice on how to stop the fan from momentarily racing, short of replacing the fan or the motherboard.  I could not find any driver for the fan using HP Support Assistant.

Thanks in advance.

PLEASE READ THE ABOVE IN ITS  ENTIRETY BEFORE OFFERING ADVICE.

[Bill_To]

Greetings @JohnnyAllentow 

Welcome to the HP Forum.

Keep an eye on the BIOS screen at startup. It looks like the BIOS update may have fixed this.

I have a newly built DIY PC with top notch components including Noctua (CPU and case) fans.

The PC's fans momentarily ramp up during a cold restart. The fans immediately settle down, the PC runs great.

I would not sweat the small stuff if your PC works as intended. 

Regards

[JohnnyAllentow]

Thanks, Bill_To

It's nice to know someone else has had the same problem and applied the same "fix" (I hope).  Time will tell I guess.

What I can't figure out is why the fan started racing only lately.  The computer is around 5 years old.

[Bill_To]

Greetings @JohnnyAllentow 

My pleasure.

This might be a point of interest if this behavior is recent. Are all fans acting this way or is only one fan ramping up? If one fan, which fan is doing this?

The BIOS checks all hardware at startup so it could be time to replace fans or it could be MB fan sensor related.

Keep an eye on this behavior. Try new fans if this gets worse over time.

Regards

[JohnnyAllentow]

I think it's only the CPU fan, but I'm not sure.  The fan seems to be impossible to remove, as there are no screw heads for the posts that mount the fan over the cooling fins.

[Bill_To]

Greetings @JohnnyAllentow 

Thanks for the additional info.

I don't think you have provided a specific HP PC Product number. HP does different CPU cooling stuff in various MBs.

You may have to redo CPU thermal paste. Or do a new CPU fan or replace the CPU air cooler.

The CPU heatsink should be attached to the MB using four T15 Torx screws. The fan may be clipped or permanently attached to the heatsink.

I have built many PC's over the years but have limited experience with HP MBs. 

I might be able to provide CPU cooler upgrade options once I know what HP PC you have.

But I would carry on with the current CPU cooler if general use CPU temps are okay.

Regards