iMac Early 2009 24-Inch, Fans Constant When Using It

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My iMac Early 2009 24-Inch computer's Northbridge Die and Heatsink are running hot. The fans come on and go full blast. This started a week ago and occurred only one time. Now it is any time I use the computer.

The newest symptom is the screens flickering. I had another monitor hooked up to the iMac. I since disconnected it because the flickering was so bad. Then the iMac screen started flickering late yesterday.

I'm running iStat to monitor the fluctuations in the temperature.

Current temperatures with fans running full blast (in F degrees):

Northbridge Die 159

Northbridge Heatsink 149

Northbridge Proximity 137

Could it be my Logic Board and/or the Graphic Card going bad?

Prior to this I've thought of getting a new iMac. Should I forget trying to repair these item(s) and buy a new iMac?

Thank you.
 

chscag

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Welcome to our forums.

Before you decide on getting a new Mac, why don't you open up your iMac and do some trouble shooting. It could be that all you need to do is remove the old thermal paste on the CPU and apply new thermal paste. But it could also mean the graphics card is dying. You could also have a thermal sensor out of whack. Since the machine is going on 9 years old, you really have nothing to lose by trying to do the repair yourself.

Opening up your iMac is much easier than the newer models since the display on your iMac is held in place by magnets. Look at the instructions for getting into your iMac at www.ifixit.com and then decide what to do.
 

Raz0rEdge

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While you've opened up the iMac, be sure to clean out any dust in there. The iMac sucks cool air from the bottom and runs it over the component and the hot air is expelled from the top. If the bottom is dusty, then not enough air is flowing through cuz causing the higher temps and the fans running harder to contain the temps.
 

Raz0rEdge

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Depends on your environment. I've never had to any cleaning on my 2009 iMac.
 
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Has the bhard drive been replac ed as Intel Macs, most models, use a heat sensor kit if an identical model drive to the original is not used? OWC sell them.
 
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Has the hard drive been replaced as Intel Macs, most models, use a heat sensor kit if an identical model drive to the original is not used? OWC sell them.

The HDD was upgraded to a 2TB in 2016. Done by Apple certified shop. I haven't had any problems with it.

When the fans kick in the CPU runs at 3600 +/- rpm. Is that the fan running at that speed? Shows this stat on iStat.
 
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hi yes that means the CPU fan is running at full speed
due to high temperatures inside the Mac or on the CPU

as advised the thermal paste is old if its never been changed and also there could be dust inside the unit despite it being cleaned in 2016

(wait did I just comment on a old post)
 

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