MBP keeps shutting down by itself (due to heat issues)

[mgpg89]

I use my MBP (Unibody, 2.8Ghz, 4GB RAM, running 10.6) in clamshell mode connected to an Apple Cinema Display ... Been doing that for a year and a half now and never had any problems.

Now, since a week or so, my MBP keeps shutting down randomly, probably due to heat issues.
So I installed SMCFanControl and run it at max RPM. Still no help.
My system reaches over 90°C before it shuts down.
Now I disconnected my MBP from everything (ACD, speakers, external HD, iPhone dock, Ethernet cable) and when running on its own off battery power, the temperature has already dropped down to 60°C and it stopped shutting down.

How can I resolve this issue? (please note: I'd like to keep using the MBP in clamshell mode with my ACD)

 

[ryannazaretian]

Open up the bottom cover and blow it out using canned air.

If you want to get it really clean (which I recommend), taking out the fans is not a big chore (3 screws a piece, and popping out the plug), and you can get the heat sinks and fans much cleaner.

I do this every time I notice my fans running faster than normal or my laptop running hotter than normal.

 

[mgpg89]

Open up the bottom cover and blow it out using canned air.

If you want to get it really clean (which I recommend), taking out the fans is not a big chore (3 screws a piece, and popping out the plug), and you can get the heat sinks and fans much cleaner.

I do this every time I notice my fans running faster than normal or my laptop running hotter than normal.

Alright thanks, I'll give that a try. How often do you clean the fans on average?

 

[ryannazaretian]

Every one or two months I guess. I take my laptop everywhere, so it gets dirty pretty fast. I also use it on my lap and bed quite a bit, so dust from that gets in it pretty quickly.

 

[mgpg89]

In the past year and a half, I have never had heat issues ... sure, my MBP got hot, but never so hot that it would automatically shut down.

So it got me thinking what could cause this? (must be software related because externally nothing has changed ... same setup as always, same temperature in the room etc ...)

And the only thing I could think of was:
I switched from Quicksilver to Google Quick Search Box right about the time the heat issues started ... could this be related?

 

[McMoronic]

Pull up activity monitor and look for any runaway processes. If you find any, you can cancel it to see if it makes a difference. Install smc and run fans at 6000. Clamshell mode isn't optimum since it tends to retain heat. All in all seems like an OS issue that a pram reset would fix. Check with apple if you have applecare tho.

 

[turugara]

You could always reset the heatsinks with better thermal grease. iFixit has a pretty good guide on how to take your laptop apart piece by piece.