View Full Version : G73 SW fan keeps blowing hard, but no heat coming out of it.

01-14-2018, 10:27 AM
I have a G73 SW bought in 2011 that suddenly started blowing one fan really hard and loud. I have also noticed some sluggishness in Windows 10, but that's subjective and I wonder if the loud fan sounds might be having a psychosomatic effect on me.

From the user's perspective, the fan that is blowing is the left fan (back of the ESC, F1, F2, and F3 keys), which is to cool the CPU. The fan blows at 100% upon reboot and even before the system launches Windows. There are no fan speed controls in the BIOS on this machine, nor do I have any way to control the fans from Windows.

The CPU has not been running hot, and I wasn't doing anything strenuous when it first failed, but seeing as how this machine is about to enter its 8th year of service, I decided to go ahead and do a repaste for the GPU and CPU. I had a fairly low expectation that this would fix the problem, but I decided that after so many years of use, the laptop could use a good dusting. Using the iFixit instructions and a few other web resources, I disassembled my laptop, cleaned up the old thermal paste, and applied it brand new.

The nasty cruft inside was not "that" bad and the cooling fins were not so clogged as to interrupt airflow. But I did find the old TIM pads were pretty cracked and crusty, so it surely was a good idea to give everything a firm cleaning and put some fresh paste on the GPU and CPU.

I reassembled, and found that the fan still blows at 100%. As I type this post, it's about 77 degrees in my house and the CPU fan is blowing cold air.

That's okay, I was not convinced that this would work anyway. But now it's time to go farther.

So a question:

How often is a fan blowing at 100% due to ...

1. ...a bad temperature probe on the CPU or motherboard?
2. ...a bad driver?
3. ...a bad card?
4. ...a bad fan?

I'm thinking maybe it could be the fan has gone bad and can't properly send the fanspeed or take orders. I thought of just buying both fans new and installing them, but on the other hand, I think I'd rather avoid spending money right now and instead save up for a whole new laptop and not pursue constant fixes for this machine. I'll still buy the fans if you folks tell me if that might be the problem.

Your thoughts?